The high-nuclearity polyoxovanadate-based carboxylate derivative K6H [(V17V12IV)-V-V(OH)(4)O-60(OOC(CH2)(4)COO)(8)]center dot nH(2)O (1) has been successfully synthesized by conventional aqueous methods and structurally characterized. The [(V17V12IV)-V-V(OH)(4)O-60(OOC(CH2)(4)COO)(8)](7-) polyanion is built up from three cages: one {V-17(V)(OH)(4)O-44} cage and two identical [((V3O6)-O-IV)(2)(OOC(CH2)(4)COO)(4)](8-) cages. Of the three cages, the {V-17(V)(OH)(4)O-44} is a purely inorganic polyoxovanadate cluster, whereas each of the [((V3O6)-O-IV)(2)(OOC(CH2)(4)COO)(4)](8-) cages is a vanadium-based organic-inorganic hybrid cluster framed via four adipate ligands linking simultaneously to two triangular {V-3} units. The two [((V3O6)-O-IV)(2)(OOC(CH2)(4)COO)(4)](8-) cages are covalently attached to the central {V-17(V)(OH)(4)O-44} cage via V-O-V bonds in a linear arrangement, resulting in a {V-29}-based hybrid cluster skeleton. The catalytic properties of compound 1 for the oxidation of sulfides by tert-butyl hydroperoxide were investigated, and the result indicates that 1 exhibits excellent catalytic activity for the oxidation of sulfides under mild conditions.