1-[2-(Carboxy-meth-oxy)phen-yl]-N-(4-chloro-phen-yl)methanimine oxide.

In the title resonance conformer, C(15)H(12)ClNO(4), the central C-N bond [1.297 (2) Å] has considerable double-bond character and the N-O bond [1.3215 (18) Å] indicates formal negative charge on the oxygen atom. Considerable deviations from co-planarity are evident in the mol-ecule, with both benzene rings twisted out of the central C-C-N-C plane [the dihedral angle formed between the rings = 81.99 (8)°]. Similarly, the carboxylic acid residue occupies a position almost normal to the plane of the benzene ring to which it is connected [C-C-O-C torsion angle = -78.42 (17)°]. The most prominent inter-molecular inter-actions involve the carboxylic acid the N(+)-O(-) residues with the O-H⋯O hydrogen bonds leading to helical supra-molecular chains along the b axis. These chains are connected into layers via C-H⋯O(carbon-yl) inter-actions and the layers are consolidated into the crystal structure by C-H⋯Cl contacts.