Research News: Molecular optoelectronic devices require, first, the design of a molecular entity whose chemical functions are reversibly triggered by external light signals and, second, integration with a solid support capable of electronic transduction of the photostimulated chemical processes at the molecular level. Two ways of functionalizing electrode surfaces are reviewed that fulfill these requirements, including a chemical system that mimics the function of a logic ''AND'', i.e., an amplified amperometric signal is obtained only when two conditions are met simultaneously.