Zwitterionic (E)-1-[(4-nitro-phen-yl)iminio-meth-yl]naphthalen-2-olate.

The title compound, C(17)H(12)N(2)O(3), was synthesized by the reaction of 2-hy-droxy-1-naphthaldehyde with 4-nitro-benzenamine. These condense to form the Schiff base, which crystallizes in the zwitterionic form. In the structure, the keto-amino tautomer has a fairly short intra-molecular N-H⋯O hydrogen bond between the 2-naphthalenone and amino groups, with electron delocalization. The mol-ecule is essentially planar, with a dihedral angle of 1.96 (3)° between the ring systems. In the crystal, the mol-ecules are linked via inter-molecular C-H⋯O hydrogen bonds, forming a layer parallel to (101).