The title compound, C16H16N2O4·3H2O, was synthesized from (1R,2R)-1,2-bis(2-hydroxyphenyl)ethylenediamine and terephthalaldehydic acid. The compound crystallizes from water as a double zwitterion with protonated amine groups and deprotonated carboxylate groups. The dihedral angle formed by the aromatic rings is 3.86 (11)°. In the crystal, N—H...O and O—H...O hydrogen bonds link molecules into a three-dimensional network.
