The synthesis and characterization of a series of picoplatin-based (picoplatin = [PtCl2(mpy)(NH3)], mpy = 2-methylpyridine), Pt(IV) complexes with axialcarboxylatoligands of increasing length are reported. The synthesis is based on the oxidation with hydrogen peroxide of picoplatin to give the cis,cis,trans-[PtCl2(mpy)(NH3)(OH)2] intermediate and then its transformation into the dicarboxylato complexes