Two new supramolecular assembly hexadecavanadate derivatives of H-2[Cd(phen)(3)](2){[Cd(H2O)(phen)(2)](V16O38Cl)}.2.5H(2)O 1 (phen = 1,10'-phenanthroline) and H-2[Cd(bipy)(3)][Cd(H2O)(bipy)(2)]{[Cd(H2O)(bipy)(2)](V16O38Cl)} center dot 1.5H(2)O(2) (bipy = 2,2'-bipyridine), have been prepared under mild hydrothermal conditions and structurally characterized by IR, XPS spectra, TG analyses and single-crystal X-ray diffraction. Compounds 1 and 2 are constructed from single pendant [CdL2] (L = phen, 1 and L = bipy, 2) modified hexadecavanadates. The hybrids 1 and 2 were used as solid bulkmodifier to fabricate bulk-modified carbon paste electrodes (CPEs) (1-CPE and 2-CPE) by direct mixing. The electrochemical behaviors and electrocatalysis of 1-CPE and 2-CPE indicate bifunctional electrocatalytic activities toward both the oxidation and reduction of nitrite. Furthermore, their electrocatalytic activities toward the reduction of bromate and oxidation of ascorbic acid are also studied in 1 M H2SO4 aqueous solutions. (c) 2006 Elsevier Ltd. All rights reserved.