In the title compound, C(15)H(14)N(2)O(4), the dihedral angle between the benzene rings is 40.59 (4)° and an intra-molecular O-H⋯N hydrogen bond generates an S(6) ring. In the crystal, N-H⋯O, O-H⋯O and C-H⋯O inter-actions link the mol-ecules into a three-dimensional network.