Disclosed are a conductive thienyl derivative monomolecular film covalently bonded to a substrate surface and method of manufacturing the same, and a silicon compound comprising 3-thienyl groups (thiophene derivative) used for forming the conductive monomolecular film and a method of manufacturing the same. A monomolecular ultrathin film comprising 3-thienyl groups and silicon groups is formed in the invention. The silicon compound used for forming the film is provided by reacting .omega.-(3-thienyl)-1-alkene compound to a monosilane derivative compound, in which three out of four hydrogen atoms of monosilane are replaced with halogen or alkoxy groups, in the presence of a transition metal catalyst. A substrate is dipped and held in a nonaqueous solution of the above-noted compound, thus chemically bonding the monomolecular film to the substrate surface. Furthermore, a thienyl derivative ultrathin film is formed by the electrolytic or catalytic polymerization of the monomolecular film.