Ligands with conjugated π-electrons, as well as the ligands complexing metal ions are synthesized, whose ordered assemblies and properties are studied in detail. As optoelectronic molecular devices, relationship between the molecular packing in ultrathin films of these compounds and the characteristic properties are focused. Ordered assemblies of amphiphilic molecules, inorganic nanoparticles and complexes at interfaces are all studied to construct functional ultrathin films.