Adsorption-induced self-organization is a new concept for “wet process” techniques for preparing highly ordered molecular adlayers by spontaneous adsorption in aqueous solution. The essential step is a thermodynamically controlled “mild” adsorption, which makes possible rapid surface diffusion and adsorption/desorption equilibrium. 2D-supramolecular structures of various molecules were possible to be constructed by choosing a proper substrate and an electrode potential, that is controlled adsorption STM visualization of highly ordered molecules provides fundamental data on intermolecular interactions.