Two new cadmium-substituted polyoxovanadates of [Cd(dien)2]2[(dien)CdAs8V13O41(H2O)].4H2O and [Cd(en)2]2[(en)2Cd2As8V12O40] (2), where dien is diethylenetriamine and en is ethylenediamine, have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, EPR spectra, XRD spectra, TG analyses, magnetic properties, and X-ray crystallography. Single-crystal X-ray diffraction analyses reveal that compounds 1 and 2 possess a discrete and 1D structure, respectively. The former contains an inorganic-organic hybrid monocadmium-substituted polyoxovanadate cluster unit that is derived from the well-known {As8V14O42} cluster, whereas the latter is composed of an inorganic-organic hybrid bicadmium-substituted polyoxovanadate cluster unit that is derived from the well-known {As8V12O40} cluster.