The crystal of the title compound, 0.6C(14)H(12)N(2)O(3)·0.4C(14)H(12)N(2)O(3), contains a mixture of its neutral (OH containing) and zwitterionic (NH containing) forms, in a 0.60 (4):0.40 (4) ratio. The former generates an S(6) loop via an intra-molecular O-H⋯N hydrogen bond and the latter generates an S(6) loop via an N-H⋯O hydro-gren bond. The aromatic rings are oriented at a dihedral angle of 42.52 (10)°. In the crystal, C-H⋯π inter-actions occur and aromatic π-π stacking inter-actions [centroid-centroid separations = 3.7106 (12) and 3.9177 (13) Å] consolidate the packing.