Biscrown stilbene S forms complexes of 1:1 and 2:1 composition with bisammonium viologen salt V4+ in acetonitrile solution. Both of the complexes exhibit spectroscopic behavior typical of molecular electron donor-acceptor complexes. The 1:1 complex [S.V](4+) has a very high thermodynamic stability (log K = 9.08), which is due to simultaneous interaction of the two ammonium groups of V4+ with the two 18-crown-6-ether units of S. The 2:1 complex (log K = 12.28) [S.V.S](4+) likely has a sandwich-type layered structure in which the acceptor salt is located between two complexed molecules of the biscrown stilbene.