Exhibit 99.1

ACACIA
RESEARCH
CORPORATION

                                                        Contacts:  Bret L. Undem
                                                                 Media Relations
                                                               Tel.(425)493-2293
                                                               Fax.(425)493-2010

FOR RELEASE
-----------
May 20, 2003

                     COMBIMATRIX GROUP RECEIVES $4.9 MILLION
                     FROM ACACIA RESEARCH PRIVATE PLACEMENT

         Newport Beach, Calif. - (BUSINESS WIRE) - May 20, 2003 - Acacia
Research Corporation (Nasdaq: CBMX:ACTG) announced today that it has completed a
private placement of approximately 2.4 million units of its Acacia
Research-CombiMatrix common stock and warrants at a price of $2.20 per unit.
Each unit consists of one share of Acacia Research-CombiMatrix common stock and
one-half warrant. Each full warrant has an exercise price of $2.75 per share of
Acacia Research-CombiMatrix common stock. Net proceeds of approximately $4.9
million from the private placement have been allocated by Acacia to its
CombiMatrix Group.

         Dr. Amit Kumar, CEO & President of CombiMatrix commented, "This
additional capital will give CombiMatrix Group the flexibility to take advantage
of current opportunities."

         Acacia expects to file a registration statement on Form S-3 no later
than 60 business days after the closing of the transaction for purposes of
registering the resale of the shares of Acacia Research-CombiMatrix common stock
issued in the private placement and issuable upon exercise of the warrants.

ABOUT ACACIA RESEARCH CORPORATION

Acacia Research Corporation comprises two operating groups, Acacia Technologies
Group and CombiMatrix Group. The CombiMatrix group is developing a platform
technology 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. CombiMatrix's technology has a wide range of
applications, from DNA synthesis/diagnostics to immunochemical detection.
Information about Acacia Research Corporation and the Acacia Technologies group
is available at www.acaciaresearch.com. Information about the CombiMatrix group
is available at www.combimatrix.com.



The Acacia Technologies group licenses its DMT and V-Chip technologies to media
and electronics companies. The DMT technology covers the transmission and
receipt of digital audio and digital video content, commonly known as audio
on-demand, video on-demand, and audio/video streaming, and is supported by 5
U.S. and 17 international patents.

Acacia Research-Acacia Technologies (Nasdaq: ACTG) and Acacia
Research-CombiMatrix (Nasdaq:CBMX) are both classes of common stock issued by
Acacia Research Corporation and are intended to reflect the performance of the
respective operating groups and are not issued by the operating groups.


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 ECONOMIC 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.

This press release shall not constitute an offer to sell or a solicitation of an
offer to buy, nor shall there be any sale of these securities in any state or
jurisdiction in which such an offer, solicitation or sale would be unlawful
prior to registration or qualification under the securities laws of any such
state or jurisdiction.