A novel proton-transfer compound, (pipzH2)(3,5-pydc), was synthesized from the reaction of pyridine-3,5-dicarboxylic acid (3,5-pydcH2) and piperazine (pipz). The crystal structure was determined by single-crystal X-ray diffraction. This compound crystallized in the monoclinic system and space group P21/c with four formula units in the unit cell. The unit cell parameters are: a = 8.076(2)Å, b = 12.842(3)Å, c = 11.571(3)Å, and β = 105.97(2)°. The final R value is 0.0320 for 5125 measured reflections. The most important feature of this crystal is the presence of N–H·O, N–H·N and C–H·O hydrogen bonds with D·A distances ranging from 2.679(1) to 3.289(2)Å. These interactions connect the various fragments into a supramolecular structure.
