The title compound, C(12)H(10)N(2)O(6), was synthesized via a Knoevenagel condensation and crystallized from ethanol. In the crystal, strong classical inter-molecular O-H⋯O hydrogen bonds and weak C-H⋯N contacts link the mol-ecules into ribbons extending along [010]. Intra-molecular O-H⋯O and C-H⋯N contacts support the planar conformation of the mol-ecules (mean deivation 0.0270 Å).