4-[(4-Chlorophenyl)(hydroxy)methylidene]isochromane-1,3-dione

3-Hydroxy-3-methylisochroman-1-one–2-(carboxymethyl)benzoic acid (1/1)

The title co-crystalline compound, C10H10O3·C9H8O4, has been synthesized and characterized in a single-crystal X-ray diffraction study. In the 3-hydroxy-3-methylisochroman-1-one molecule, the six-membered heterocyclic ring lies between an envelope and a screw-boat conformation. In the 2-carboxymethylbenzoic acid, molecule, the 2-carboxymethyl substituent is almost planar (r.m.s deviation = 0.048 Å) and makes a dihedral angle of 79.59 (7)° with the planar benzene ring. In this molecule, intramolecular C—H...O contacts generate five- and six-membered rings, forming a tricyclic ring system. In the crystal, classical O—H...O and C—H...O hydrogen bonds combine with C—H...π(ring) and unusual C=O...π(ring) contacts to generate a three-dimensional network.