February 12, 2004


GraphOn Corporation
105 Cochrane Circle
Morgan Hill, California  95037

            Re:   Registration Statement on Form S-3
                  Under the Securities Act of 1933

Ladies and Gentlemen:

      In our capacity as counsel to GraphOn Corporation, a Delaware corporation
(the "Company"), we have been asked to render this opinion in connection with a
Registration Statement on Form S-3 ("Registration Statement") being filed
contemporaneously herewith by the Company with the Securities and Exchange
Commission under the Securities Act of 1933, as amended (the "Act"), covering
(i) 5,000,000 shares of common stock, par value $0.0001 per share, of the
Company ("Shares"), and (ii) 3,250,000 shares of common stock, par value $0.0001
per share, of the Company ("Warrant Shares") that are presently issuable upon
future exercises of certain warrants heretofore issued by the Company (the
"Warrants"). The Shares and the Warrant Shares have been included in the
Registration Statement for the account of the persons identified therein as the
Selling Stockholders.

      In that connection, we have examined the Amended and Restated Certificate
of Incorporation and Amended and Restated By-Laws of the Company, the
Registration Statement, corporate proceedings of the Company relating to the
issuance of each of, respectively, the Shares, the Warrants and the Warrant
Shares and such other instruments and documents as we have deemed relevant under
the circumstances.

      In making the aforesaid examinations, we have assumed the genuineness of
all signatures and the conformity to original documents of all copies furnished
to us as original or photostatic copies. We have also assumed that the corporate
records furnished to us by the Company include all corporate proceedings taken
by the Company to date.

      Based upon and subject to the foregoing, we are of the opinion that:

      1. The Shares have been duly and validly authorized and issued, and are
fully paid and non-assessable; and

      2. The Warrant Shares have been duly and validly authorized and, when
issued and paid for in accordance with the terms of the Warrants and as
described in the Registration Statement, will be duly and validly issued, fully
paid and non-assessable.

      We hereby consent to the use of our opinion as herein set forth as an
exhibit to the Registration Statement and to the use of our name under the
caption "Legal Matters" in the prospectus forming a part of the Registration



Statement. We do not, by giving such consent, admit that we are within the
category of persons whose consent is required under Section 7 of the Act.

                                    Very truly yours,

                                    SONNENSCHEIN NATH & ROSENTHAL LLP



                                    By:   /s/ IRA I. ROXLAND
                                      ----------------------------------
                                         A Member of the Firm