1-(4-Cyanophenyldiazen-2-ium-1-yl)-2-naphtholate

In the molecule of the zwitterionic title compound, C17H11N3O, the naphthalene ring system is planar [maximum deviation = 0.029 (3) angstrom] and is oriented at a dihedral angle of 3.55 (3)degrees with respect to the benzene ring. An intramolecular N-H center dot center dot center dot O hydrogen bond results in the formation of a planar six-membered ring. In the crystal structure, intermolecular C-H center dot center dot center dot O interactions link the molecules into centrosymmetric dimers.