The title salt, NH4+·H+·2C14H9N4O2−, is composed of an ammonium cation with a strong intermolecular negatively charge-assisted hydrogen-bonded acid/conjugate base-pair monoanion. The carboxylic acid H atom is located on an inversion center, while the N atom of the ammonium cation is located on a twofold rotation axis. In the crystal, the N—H bonds of each ammonium cation act as donors with carboxylate O-atom acceptors to form chains along the a-axis direction. The chains are linked by offset π–π interactions [intercentroid distances = 3.588 (2) and 3.686 (2) Å], forming layers parallel to the ab plane.
