ZrOCl2· 8H2O catalyzed environmentally benign synthesis of isobenzofuran-1 (3H)-ones are described. ZrOCl2· 8H2O appeared to be an excellent catalyst for the condensation and reactions. Reaction of phthalaldehydic acid (2-carboxybenzaldehyde) with methylaryl and cyclic ketones was initiated by condensation and occurred in one step providing excellent yields (90–98%).