2,3-Diamino-pyridinium 4-carb-oxy-butano-ate.

In the title mol-ecular salt, C(5)H(8)N(3) (+)·C(5)H(7)O(4) (-), the 2,3-diamino-pyridine mol-ecule is protonated at the pyridine N atom. The cation is essentially planar, with a maximum deviation of 0.015 (2) Å, and the anion adopts an extended conformation. In the crystal, the hydrogen glutarate (4-carb-oxy-butano-ate) anions are self-assembled through O-H⋯O hydrogen bonds, forming chains. The cations are connected to the anion chains via N-H⋯O hydrogen bonds, forming a three-dimensional network. The crystal structure also features aromatic π-π inter-actions between the pyridinium cations, with a centroid-centroid distance of 3.4464 (10) Å.