The photodimerization and its photochemical reversal of the pendent anthryl groups in 10-thiodecyl 2-anthryl ether (1) as a self-assembled monolayer on polycrystalline gold are evaluated as a photochromic surface fluorescence switch. Evidence for SAM-photoresponsiveness was gathered from surface fluorescence and surface reflectance infrared spectroscopic measurements in which changes in the monolayer were monitored before and after irradiation at 350 and 254 nm. Contact angle measurements confirmed the presence of a hydrophobic surface in the self-assembled monolayer Au-1. Electrochemical measurements of the resulting monolayer, before and after irradiation at 350 and 254 nm, indicate that the stable monolayers insulate the gold electrode from electrical contact with redox couples present in a contacting solution. These effects are interpreted by comparison with the solution phase photochemistry of the acetyl precursor of 1.