Vacuum-annealed highly boron-doped diamond (BDD) thin-film electrodes are shown to allow reversible voltammetric responses for the reduction of nitrobenzene, 3,5-difluoronitrobenzene, and for the generation of solvated electrons in liquid ammonia at -60 degrees C. In liquid ammonia (0.1 M KI) a considerably extended positive potential window at BDD electrodes compared to platinum is observed. At the negative end of the potential scale facile generation of solvated electrons occurs at both platinum and BDD electrodes. After exposure to solvated electrons in liquid ammonia, the surface of the diamond becomes hydrophilic and nitrogen functionalities were detected by X-ray photoelectron spectroscopy.