Reactions of [Sb^IIIBr₆]^3– with Br₂ in HBr in the presence of N-substituted quinolinium or isoquinolinium cations result in new complexes of hexabromidoantimonates of Sb^V and their polybromide adducts: (N-MeQuin)₂{[SbBr₆](Br₃)} (1), (N-MeIsoquin)₂{[SbBr₆](Br₃)} (2), and (N-EtQuin)[SbBr₆] (3). Thermal stability was studied; estimated energies of supramolecular Br···Br interactions were calculated.