CombiMatrix to Hold Conference Call to Discuss Business Strategy for CombiMatrix Molecular Diagnostics.

NEWPORT BEACH, Calif. -- Acacia Research Corporation (Nasdaq:ACTG) (Nasdaq:CBMX) announced today that its CombiMatrix group will host a CombiMatrix Molecular Diagnostic Business Overview and Strategy conference call on Monday, May 23, 2005. The call will include a slide presentation and will be led by Dr. Amit Kumar, Mr. Matt Watson, and Dr. David Baunoch.

The conference call will begin at 1:30 p.m. Pacific Time (4:30 p.m. Eastern) and a Q&A session will follow.

To listen to the presentation by phone, dial [phone] for domestic callers and [phone] for international callers, both of whom will need to provide the operator with the confirmation code 9629640. A replay of the audio presentation will be available for 30 days at [phone] for domestic callers and [phone] for international callers, both of whom will need to enter the code 9629640 when prompted.

The call is being webcast by CCBN and will include a slide presentation. The webcast can be accessed at CombiMatrix's website at www.combimatrix.com/news_events.htm.

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 arrays, which are semiconductor-based tools for use in identifying and determining the roles of genes, gene mutations and proteins. The CombiMatrix's group's technology has a wide range of potential applications in the areas of genomics, proteomics, biosensors, drug discovery, drug development, diagnostics, combinatorial chemistry, material sciences and nanotechnology.

The Acacia Technologies group develops, acquires, and licenses patented technologies. Acacia controls 30 patent portfolios, which include 128 U.S. patents, and certain foreign counterparts, covering technologies used in a wide variety of industries including audio/video enhancement & synchronization, broadcast data retrieval, computer memory cache coherency, credit card fraud protection, database management, data encryption & product activation, digital media transmission (DMT(R)), digital video production, dynamic manufacturing modeling, enhanced Internet navigation, image resolution enhancement, interactive data sharing, interactive television, Internet access redirection, interstitial Internet advertising, laptop docking station connectivity, microprocessor enhancement, multi-dimensional bar codes, network data storage, resource scheduling, rotational video imaging and spreadsheet automation.

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.

Information about the Acacia Technologies Group and the CombiMatrix Group is available at www.acaciaresearch.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 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.