Self-assembled monolayers (SAMs) of mu(3)-eta(2):eta(2):eta(2)-C-60 triosmium cluster complex Os-3(CO)(8)(CN(CH2)(3)-Si(OEt)(3))(mu(3)-eta(2):eta(2):q2-C-60) (2) on ITO or An surface exhibit ideal, well-defined electrochemical responses and remarkable electrochemical stability being reducible up to tetraanionic species in their cyclic voltammograms.