1 EXHIBIT 5.--OPINION OF COUNSEL FROST & JACOBS LLP 2500 PNC Center 201 East Fifth Street Post Office Box 5715 Cincinnati, Ohio 45201-5715 (513) 651-6800 March 3, 1999 First Financial Bancorp. 300 High Street Hamilton, Ohio 45012-0476 Re: First Financial Bancorp. Form S-4 Registration Statement ------------------------------- Gentlemen: We are counsel for First Financial Bancorp., an Ohio corporation (the "Company"), which is named as the registrant in the Registration Statement on Form S-4 which is being filed on or about March 3, 1999 with the Securities and Exchange Commission for the purpose of registering under the Securities Act of 1933, as amended (the "Act"), certain common shares, without par value (the "Common Shares"), of the Company. With respect to the Common Shares being registered pursuant to such Registration Statement as filed and as it may be amended, it is our opinion that the Common Shares, when issued and paid for pursuant to the Plan and Agreement of Merger dated as of December 16, 1998 between First Financial Bancorp. and Sand Ridge Financial Corporation, will be validly issued, fully paid and non-assessable. We hereby consent to the reference to our firm under the caption "Legal Matters" in the Registration Statement. Very Truly Yours, Frost & Jacobs LLP NG/gam