Bis[3-allyl-1-(4-cyanobenzyl)-2-methylbenzimidazolium] di-μ-bromido-bis[bromidocuprate(I)].

The asymmetric unit of the title compound, (C(19)H(18)N(3))(2)[Cu(2)Br(4)], contains one cation and one half-anion; there is a centre of symmetry mid-way between the two Cu atoms. In the cation, the nearly planar benzimidazole ring system is oriented at dihedral angles of 75.31†(3) and 21.39†(3)° with respect to the cyano-benzyl and allyl groups, respectively. The dihedral angle between cyano-benzyl and allyl groups is 87.94†(3)°. In the crystal structure, inter-molecular C-H⋯Br hydrogen bonds link the mol-ecules. There is a C-H⋯π contact between the cyano-benzyl ring and the anion; π-π contacts also exist between the benzimidazole ring systems as well as between the anion and the cyano-benzyl ring [centroid-centroid distances = 4.024†(1) and 4.617†(1)†à , respectively].