The title compound, C3H12N2 2+C7H3NO4 2C7H5NO4 2.5H2O, is a proton-transfer system obtained from pyridine- 2,6-dicarboxylic acid and propane-1,3-diamine. Both neutral and dianionic forms of the diacid are observed in the crystal structure. The molecular structure contains also the diprotonated form of propane-1,3-diamine as well as water molecules. In the crystal structure, a wide range of hydrogen-bonding interactions connect the various fragments into a supramolecular structur