In the title compound, C(15)H(12)N(2)O(7), the dihedral angle between the aromatic rings is 4.58 (13)° and the nitro group is rotated from its attached ring by 18.07 (17)°. Intra-molecular N-H⋯O and O-H⋯O hydrogen bonds generate S(5) and S(6) rings, respectively. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, generating [001] C(7) chains. The chains are linked by C-H⋯O inter-actions, forming a three-dimensional network, which incorporates R(2) (2)(7) and R(2) (2)(10) loops.