Two compounds, namely, [Cu(bbi)](2)[Cu-2(bbi)(2)(delta-Mo8O26)(0.5)][alpha-Mo8O26](0.5) (1) and [Cu(bbi)][Cu(bbi)(theta-Mo8O26)(0.5)] (2), where bbi is 1,1 '-(1,4-butanediyl)bis(imidazole), were synthesized under hydrothermal conditions at different pH values. Their crystal structures were determined by X-ray diffraction. Compounds 1 and 2 are supramolecular isomers with a polythreaded topology based on octamolybdate building blocks.