FILED BY ACACIA RESEARCH CORPORATION (COMMISSION FILE NO. 000-26068)
              PURSUANT TO RULE 425 UNDER THE SECURITIES ACT OF 1933

Investors are urged to read documents  relevant to the transaction  described in
this  announcement  that are  filed  with or that  will be  filed  with the U.S.
Securities and Exchange  Commission  because they contain important  information
about the  transaction.  After  they are  filed,  you can  obtain  the  relevant
documents that are filed with the Securities and Exchange Commission for free on
the Securities and Exchange Commission's web site at http://www.sec.gov.  If you
write or call us, we will send you for free, when available, the prospectus that
we file in connection  with the  registration  of the shares to be issued in the
acquisition. You can call us at (949) 480-8300 or write to us at:

Acacia Research Corporation
500 Newport Center Drive, 7th Floor
Newport Beach, California  92660
Attention: Investor Relations



                    [ACACIA RESEARCH CORPORATION LETTERHEAD]


                                                               INVESTOR CONTACT:
 FOR IMMEDIATE RELEASE                                              Rob Stewart
 March 20, 2002                                                    949-480-8300


  ACACIA RESEARCH ANNOUNCES PLAN TO CREATE SEPARATE NASDAQ LISTED PUBLIC SHARES
             FOR ITS COMBIMATRIX AND ACACIA TECHNOLOGIES BUSINESSES


     NEWPORT BEACH,  Calif.--(BW  HealthWire)--March  20, 2002--Acacia  Research
Corporation  (Nasdaq:ACRI)  announced  today  that its  Board of  Directors  has
approved  a plan  to  divide  its  common  stock  into  two new  classes  -- new
"CombiMatrix"  stock,  that would  reflect  the  performance  of its  subsidiary
CombiMatrix Corporation, and new "Acacia Technologies" stock, that would reflect
the performance of Acacia's media technology businesses.

     The plan will be submitted to the Company's stockholders for approval.

     If the plan is approved,  Acacia Research stockholders would receive shares
of both of the new  classes of stock in  exchange  for the shares they now hold,
and the new shares would be separately traded Nasdaq listed public securities.

     Paul R. Ryan,  Chairman and CEO of Acacia  Research,  said: "We believe the
separately  traded shares would increase market awareness of the performance and
value  of our two  distinct  businesses,  increase  investor  interest,  attract
industry-specific   investors   and  better   enable  us  to  pursue   strategic
opportunities.  This is an important step toward realizing the full market value
of our separate businesses."

     Acacia also announced that its Board of Directors and  CombiMatrix's  Board
of  Directors  have  approved an  Agreement  for Acacia to acquire the  minority
stockholder   interest  in  CombiMatrix.   The  proposed  acquisition  would  be
accomplished through a merger in which the minority  stockholders of CombiMatrix
would  receive  shares of the new  "CombiMatrix"  stock,  in exchange  for their
existing shares. The proposed  transaction will be submitted to the stockholders
of both Companies for approval.

     "CombiMatrix  minority  stockholders and Acacia Research stockholders would
both  benefit by  receiving  publicly  traded  Nasdaq  listed  shares of the new
`CombiMatrix'  stock," commented Dr. Amit Kumar, CEO & President of CombiMatrix.
"Both groups of  stockholders  would benefit from the liquidity  provided by the
new `CombiMatrix' stock if the proposals are approved," concluded Dr. Kumar.

     A.G.  Edwards  and Gerard  Klauer  Mattison  are  investment  advisors  for
CombiMatrix in the merger and William Blair & Co. will advise Acacia Research.

     Commenting  on this new  structure,  Mr.  Ryan  stated:  "To  maximize  the
potential  value of our distinct  businesses,  we are  pursuing a financial  and
operating  structure  that will allow our two  businesses  to grow as quickly as
possible.  After reviewing various alternative operating  structures,  our Board
believes this targeted approach is optimal for our situation."

     Acacia  Research's Board of Directors  believes the new stock structure can
unlock numerous  benefits for  stockholders,  achieving the following  important
objectives:

     1.   Facilitate  autonomy.  The structure  allows each business to optimize
          its own identity, business strategy and financial model.

     2.   Accommodate investor interests. The structure is designed to serve the
          interests of investors by providing separate  investment  vehicles for
          Acacia's  different  businesses,  particularly  to  the  extent  those
          businesses  operate in different  industry  sectors and have different
          characteristics and goals with respect to timing,  growth,  risks, and
          financial requirements.

     3.   Attract  institutional  research.  The  separate  stocks  would enable
          research coverage by industry specific analysts.

     4.   Targeted stock  ownership.  The structure would enable Acacia Research
          stockholders to have targeted ownership of both "Acacia  Technologies"
          stock and "CombiMatrix" stock.

     5.   Acquisition  currencies.  The Company would have two different  equity
          securities for issuance in connection with any potential acquisitions.

     The proposed  recapitalization  and merger are subject to several important
conditions,  including  receipt  of  stockholder  approval  for both  companies,
receipt of satisfactory  tax and accounting  opinions,  approval of the proposed
merger by a special committee of the CombiMatrix Board of Directors,  receipt of
a fairness opinion regarding the merger, approval for listing of both of the new
shares on Nasdaq and other customary conditions.

     Prior to the completion of the proposed  transaction,  Acacia  Research and
CombiMatrix  anticipate  that Acacia  would  convey its  majority  ownership  of
Advanced Material Sciences to CombiMatrix in exchange for CombiMatrix stock.

     Acacia Research is preparing to file a preliminary proxy statement with the
U.S.  Securities and Exchange  Commission,  and the proposals are expected to be
presented to  stockholders  for approval at a special  meeting.  Proxy materials
will be mailed to stockholders following a registration statement being declared
effective.

     This press release does not constitute an offer of any security for sale or
solicitation of an offer to buy. Any sale of the securities will be made only by
means of the prospectus included within the registration statement.

     About Acacia Research Corporation

     Acacia  Research  develops,  licenses  and  provides  products for the life
science and media technology  sectors.  Acacia licenses its V-chip technology to
television  manufacturers  and owns pioneering  technology for digital streaming
and video-on-demand.  Acacia's  CombiMatrix  subsidiary is developing a bio-chip
technology for the life science market. Acacia Research's Web site is located at
www.acaciaresearch.com.

     About CombiMatrix

     CombiMatrix  is developing a platform  technology  that has a wide range of
applications,  from DNA  synthesis/diagnostics to immunochemical  detection. The
platform allows the company to rapidly  produce  customizable  active  biochips,
which are  semiconductor-based  tools for use in identifying and determining the
roles of genes,  gene  mutations  and  proteins.  The company is  designing  its
products   principally  to  be  responsive  to  the  needs  of   pharmaceutical,
biotechnology,  and academic  researchers  in analyzing  raw genomic data in the
discovery and development of pharmaceutical products.  CombiMatrix's Web site is
located at www.combimatrix.com

     Safe Harbor Statement under the Private Securities Litigation Reform Act of
1995:

     This news release contains forward-looking statements within the meaning of
the "safe harbor" provisions of the Private Securities  Litigation Reform Act of
1995. These statements are based upon our current expectations and speak only as
of the date hereof.  Our actual results may differ materially and adversely from
those expressed in any forward-looking statements as a result of various factors
and uncertainties, including the recent slowdown affecting technology companies,
our ability to successfully develop products,  rapid technological change in our
markets, changes in demand for our future products, legislative,  regulatory and
competitive  developments and general economic conditions.  Our Annual Report on
Form 10-K, recent and forthcoming Quarterly Reports on Form 10-Q, recent Current
Reports  on Forms  8-K and  8-K/A,  and other SEC  filings  discuss  some of the
important  risk factors that may affect our business,  results of operations and
financial condition. We undertake no obligation to revise or update publicly any
forward-looking statements for any reason.


                                  End of Filing