The self-assembled monolayer (SAM) of Schiff base V-ape-V molecules on Au(I 11) in HClO4 solution has been investigated by electrochemical techniques and electrochemical scanning tunneling microscopy (ECSTM). The adsorption of V-ape-V on Au(I 11) retards the oxidization of Au and reduces the double-layer capacitance. Two-dimensional ordered molecular arrays with a (5 x 2root3) commensurate structure are observed. The V-ape-V molecules are adsorbed on Au(1 11) in a flat-lying orientation. A structural model is proposed to interpret the experimental results.