The 7-amino-2,4-dimethylquinolinium salts with a variety of anions (Cl⁻, HCOO⁻, CH₃COO⁻, PhCOO⁻, L-HOOCCH(OH)CH(OH)COO⁻) have been synthesized and characterized. The crystal structures of these salts were determined by single-crystal X-ray diffraction. The structure analysis confirms that the nitrogen atoms in the quinoline rings are protonated in all salts. The two solvates have been obtained and thereby provide a useful complement to cocrystal screening. All the quinolinium salts display interesting three dimensional supramolecular networks. The hydrogen bonding interactions observed in all of the salts are N–H⋯O, O–H⋯O and N–H⋯Cl, together with weak C–H⋯O, C–H⋯N, C–H⋯Cl hydrogen bonds. The weak C/N–H⋯π contacts and π–π stacking interactions involving the quinoline moieties also exist in quinolinium salts. The observed noncovalent interactions become prominent in stabilizing their crystal packing. The 7-amino-2,4-dimethylquinolinium salts show strong luminescence in the solid state and solution in the range 422–534 nm. The solid-state emission spectra of the quinolinium salts are sensitive to the anion species, and highly dependent on the nature of the stacking interactions.