A 1D anionic polyoxometalate, [Mn4(H2O)18WZnMn2(H2O)2(ZnW9O34)2]4–, undergoes 1D to 3D single-crystal-to-single-crystal structural transformations that are induced by transition-metal cations (Co2+ and Cu2+) and solvent molecules. These solid materials present interesting catalytic activity for the oxidative aromatization of Hantzsch 1,4-dihydropyridines that is dependent on the inserted heterogeneous metal cations.