Novel self-assembled monolayers of oxide and acetate-bridged triruthenium(III) complexes have been prepared on Au(111) electrode surface. Parent discrete triruthenium(III) complexes with a terminal disulfide ligand, [Ru-3(mu(3)-O)(mu-CH3CO2)(6)(L)(2)(C2PY)]ClO4, where C2PY = {NC5H4CH2NHC(O)(CH2)(2)S-}(2), L = 4-methylpyridine (mpy, 4a) and 1-methylimidazole (MeIm, 4b), were isolated through multistep synthesis. Complex 4a exhibits three reversible redox waves, while complex 4b exhibits two reversible and one irreversible redox waves in (n-C4H9)(4)NPF6/CH3CN, all ascribed to one-electron redox of the triruthenium cluster core. In aqueous solution containing a 0.1 M supporting electrolyte (NaClO4 or Na2SO4), self-assembled monolayers of 3a and 4b on Au(111) electrodes (4a/Au and 4b/Au) exhibit a single reversible redox wave, ascribed to the Ru,(III,III,III/II,III,III) redox process for the surface-attached clusters. The redox potential and the shape of the cyclic voltammograms of Ru, cluster modified SAMs were affected by the kind of terminal ligands and supporting electrolytes.