A novel trititanium(IV)-substituted WellsDawson polyoxometalate (POM)-based organometallic complex, i.e., a dimeric POM containing two bridging Cp*Rh2+ groups (Cp* = C5Me5) or [{alpha - P2W15Ti3O60(OH)(2)}(2)(Cp*Rh)(2)](16-) (D-1) with C-i symmetry, was synthesized in an analytically pure form by a 1:2 -molar ratio reaction of the organometallic precursor [Cp*RhCl2](2) with the separately prepared, monomeric trititanium(IV)substituted Wells-Dawson POM, "[P2W15Ti3O59(OH)(3)](9-") (M-1). The crystalline sample (NaK-D-1) of the watersoluble, mixed sodium/potassium salt of D-1 was obtained in the 14.7% yield, which has been characterized by complete elemental analysis, TG/DTA, FTIR, single-crystal X-ray structure analysis, and solution (W-183, P-31, H-1 and C-13{H-1}) NMR spectroscopy. Single-crystal X-ray structure analysis revealed that the two species of the protonated Wells-Dawson subunits, "[P2W15Ti3O60(OH)(2)](10-) were bridged by the two Cp*Rh2 groups, resulting in the an overall C, symmetry. The Cp*Rh2+ groups were linked to the two terminal oxygen atoms of the titanium(IV) sites and one edge-sharing oxygen atom of the surface Ti-O-Ti bond. The W-183 NMR of D-1 dissolved in D2O showed that its solution structure was represented as a dimeric POM with a formula of [{alpha-P2W15Ti3O60(OH)(3)}(2){Cp*Rh-(OH)}(2)](16-) (D-2) with Ci (or S-2) symmetry. A trititanium(IV)-substituted Wells-Dawson POM-supported organometallic complex has never been reported so far, and thus D-1 in the solid state and D-2 in solution are the first example of this type of complex.