In the title compound, 4C5H8N3 +·2C8H4O4 2−·C5H7N3, the asymmetric unit consists of two protonated diamino­pyridine cations, one phthalate anion and one half of a diamino­pyridine mol­ecule, which has twofold rotation symmetry and is disordered over two positions with a site-occupancy ratio of 0.534 (3):0.466 (3). In the disordered structure, both pyridine rings are essentially planar, with maximum deviations of 0.011 (2) and 0.006 (2) Å, and these two rings are inclined to one another at a dihedral angle of 79.86 (10)°. In the crystal structure, inter­molecular N—H⋯O and C—H⋯O hydrogen bonds link the ions and mol­ecules into a three-dimensional network. The structure is further stabilized by C—H⋯π inter­actions.

In the title hydrated mol­ecular salt, C7H11N2 +·Cl−·2H2O, the pyridine N atom of the 2-amino-4,6-dimethyl­pyridine mol­ecule is protonated. The cation is essentially planar, with a maximum deviation of 0.006 (2) Å. In the crystal, the components are linked by N—H⋯O, N—H⋯Cl and O—H⋯Cl hydrogen bonds, thereby forming sheets lying parallel to (100). The crystal structure is further stabilized by aromatic π–π stacking inter­actions between the pyridinium rings [centroid–centroid distance = 3.4789 (9) Å].

In the title molecular salt, C7H16N+·Cl−, the piperidinium ring adopts a chair conformation. In the crystal, the two components are connected by N—H⋯Cl and C—H⋯Cl hydrogen bonds, forming a supra­molecular double-chain structure along the c axis.