A photoisomerizable nitrospiropyran monolayer assembled on a Au electrode provides a functionalized interface for the photochemical, pH, and thermal control of electrochemical processes of charged electroactive redox probes. (Mercaptobutyl)nitrospiropyran 1 was assembled as a monolayer on a Au electrode. The monolayer exhibits reversible photoisomerizable features, and illumination of the nitrospiropyran monolayer, SP state, 320 nm < lambda < 350 nm, yields at pH = 7.0 the protonated nitromerocyanine monolayer state, MRH(+) state. Further irradiation of the MRH(+) monolayer, lambda > 495 nm, regenerates the SP state of the monolayer. The light-induced transformation of the monolayer between a neutral and a positively-charged interface allows the control of the electron transfer processes at the electrode interface. Electrooxidation of the negatively-charged (3,4-dihydroxyphenyl)acetic acid, DHPAA, is enhanced at the MRH(+) monolayer electrode as compared to the SP-functionalized monolayer electrode. Electrooxidation of the positively-charged 3-hydroxytyramine (dopamine), DOPA, is inhibited at the MRH(+) monolayer electrode as compared to its oxidation by the SP monolayer electrode. The control of the electrochemical oxidation of DHPAA and DOPA at the photoisomerizable monolayer electrode is attributed to the electrostatic interactions of the MRH(+) monolayer electrode with the redox-active substrates. Electrostatic attraction of DHPAA and repulsion of DOPA by the MRH(+) monolayer results in enhancement or inhibition of the electrochemical processes, respectively. By reversible isomerization of the monolayer between the SP and MRH(+) states, cyclic amperometric transduction of the optical signals recorded by the monolayer is accomplished.