In the title compound, C(18)H(14)N(2)O(4), the dihedral angle between the benzene ring and the naphthyl ring system is 10.1 (2)°. The mol-ecule is nearly planar, with a mean deviation from the plane of 0.141 (2) Å for 24 non-H atoms. An intra-molecular O-H⋯N hydrogen bond forms a pseudo-6-membered ring and the mol-ecules are linked into sheets by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds.