AbstractOrganic conjugated polymers can be deposited as thin films on semiconducting or conducting electrodes, and, owing to the large potential offered by varying their physical and chemical properties, new devices can be envisionned. Thus CdS and CdSe are interesting photoanodes for the photoelectrochemical conversion and storage of light energy, but they require to be protected against their very fast corrosion in aqueous solution. This is achieved by thin layers of composite conducting polymers, in which the conductivity the catalytic activity and the hydrophobic character can be controlled. Besides, conjugated polymer films possess in their undoped state semiconducting properties, and when deposited on inorganic semiconductors, they lead to new “organic‐on‐inorganic” electronic junctions. The electric characteristics of these junctions can be easily tuned by subtle chemical modifications in the polymer structure and doping level. Finally, the recent development of functionalized organic conducting polymers, in which various prosthetic groups bearing selective functions are homogeneously distributed along the conducting chains, will allow the realization of new chemically selective electronic devices.