Not intra-, but intermolecular stacking interactions between imidazole rings are responsible for the self assembly of the ainuclear Cu1 complex [Cu2L2]2+ to an infinite double-helical polymer (picture on the right) in the solid state. In recent years a range of double-helical complexes of low-molecular weight has been prepared; however, [Cu2L2]math image is the first polymeric complex of this type.