2,3-Diamino­pyridinium 4-meth­oxy­quinoline-2-carboxyl­ate

In the 4-meth­oxy­quinoline-2-carboxyl­ate anion of the title salt, C(5)H(8)N(3) (+)·C(11)H(8)NO(3) (−), the dihedral angle between the quinoline ring system and the carboxyl­ate group is 16.54 (15)°. In the crystal, the cations and anions are linked via N—H⋯O and N—H⋯N hydrogen bonds, forming a centrosymmetric 2 + 2 aggregate with R (2) (2)(9) and R (4) (2)(8) ring motifs. These units are further connected via N—H⋯O hydrogen bonds into a layer parallel to the bc plane. The crystal structure is also stabilized by weak C—H⋯O hydrogen bonds and π–π inter­actions between pyridine rings [centroid–centroid distance = 3.5886 (8) Å] and between pyridine and benzene rings [centroid–centroid distance = 3.6328 (8) Å].