Crystal structure of (E)-2-[(4-hy-droxy-benzyl-idene)aza-nium-yl]benzoate.

The title Schiff base, C14H11NO3, crystallizes as a zwitterion (i.e. proton transfer from the carb-oxy-lic acid group to the imine N atom). The dihedral angle between the aromatic rings is 19.59†(6)° and an intra-molecular N-H⋯O hydrogen bond closes an S(6) ring. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R 2 (4)(24) loops. The dimers are linked by C-H⋯O inter-actions, generating (211) sheets.