A monolayer of conducting polymer, polyaniline (PAN), was assembled on hydroxyl-terminated surfaces, such as quartz, glass, indium-tin oxide, and native oxide on Si. The approach for assembling two-dimensional monolayers of PAN is based on a chemical or electrochemical surface polymerization of electrostatically bound anilinium. The latter was bound to the negatively charged sulfonate group of mercaptoethanesulfonate that was previously coupled by an S(N)2 reaction to an iodopropyl self-assembled monolayer. The consecutive assembling steps were followed by X-ray photoelectron spectroscopy, W-vis-NIR spectroscopy, variable angle spectroscopic ellipsometry, contact angle, and atomic force microscopy measurements. The characteristic electronic properties of the PAN monolayers were studied by W-vis-NIR spectroscopy and cyclic voltametry.