Cesium acetate was found to be the best catalyst for the synthesis of 3-benzylidenephthalide from phthalic anhydride and phenylacetic acid. Reasonable to good yields of different 3-arylmethylenephthalides were isolated from the microwaveGabrielsynthesis, even when phenylthio- and 2-(3-)thienyl- acetic acids were used as the starting material.