This paper describes the synthesis of 2,9,16,23-tetrahyroxythiophenylphthalocyanato-cobalt(II) (4 beta-CoII-THTPhPc) and its self-assembly on Au surface. The self-assembled monolayer (SAM) was formed by immersing the Au electrode in dimethylformamide containing 4 beta-(CoTHTPhPc)-T-II. The SAM of 4 beta-co(II-)THTPhPc on Au electrode was characterized by cyclic voltammetry, Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The cyclic voltammogram of 4 beta-(CoTHTPhPc)-T-II SAM in HClO4 shows two pairs of redox peaks at 0.38 V and 0.53 V, corresponding to Co-III/Co-II and (CoPc1-)-Pc-III/(CoPc2-)-Pc-III, respectively. Raman and electrochemical reductive desorption studies confirm that the SAM of 4 beta-co(II-)THTPhPc was formed on Au electrode via Au-S linkage. Raman spectrum shows a characteristic stretching band at 250 cm(-1) corresponding to Au-S. Further, the electrochemical reduction of dioxygen was carried out using the SAM modified Au electrode in HClO4. The SAM modified electrode not only decreased the oxygen reduction overpotential but also enhanced its current in contrast to bare Au electrode. (C) 2013 Elsevier B.V. All rights reserved.