The asymmetric unit of the title salt, C4H12N2 2+2C7H4NO4 or pipzH2 2+2(py-2,3-dcH), prepared by a reaction between pyridine-2,3-dicarboxylic acid (py-2,3-dcH2) and piperazine (pipz), contains a monoanion and half of a centrosymmetric dication. The anionic fragment individually has two intramolecular hydrogen bonds, an almost linear O—H O bond between two carboxylate groups and a C—H O bond between the aromatic ring and carboxylate group. Other O— H O, N—H O and C—H O hydrogen bonds are responsible for three-dimensional expansion of the structur
