1-(4-Methyl-phenyl-diazo-nium-yl)-2-naphtholate.

In the title compound, C(17)H(14)N(2)O, the dihedral angle between the benzene ring and naphthalene ring system is 11.0 (3)°. The azo group adopts an anti configuration and an intra-molecular N-H⋯O hydrogen bond exists. Mol-ecules are packed by π-π inter-actions between adjacent mol-ecule (closest approach between centroids of benzene and naphthalene rings of 3.501 Å).