Adsorption of two binaphthyl derivatives on Cu(111) electrode were investigated by STM and cyclic voltammetry. Both molecules adsorbed on the Cu(1 11) electrode surface in 0.1 M HClO4 solution and formed well-defined adlayers with a (4 x 4) symmetry in the double layer potential region. With the high resolution STM images, the configurations of individual molecules were determined. According to the experimental results, structural models are proposed for the adlayers.