Reactions between BiCl₃, Br₂, and chlorides of pyridinium (1), 4,4′-propylenedipyridinium (2), or trimethylphenylammonium (3) in aqueous HCl lead to the formation of chlorobismuthate complexes trapping {Br₂} in the solid state into two-dimensional polyhalide supramolecular networks. The nature of non-covalent Br···Cl interactions was studied by theoretical methods; estimated energies of these interactions are 1.9–6.0 kcal/mol.