Oxidation is one of the most important types of transformation in chemistry, and practical mild oxidation without added reagents or solvents has been a long-standing challenge. We have developed a highly practical solvent-free (biphasic) electrochemically driven oxidation system for the selective conversion of sulfides to the corresponding sulfoxides, and alkenes to the corresponding epoxides, in a very simple reactor system. Excellent yields are obtained for a variety of substrates, and neither over-oxidation to sulfone nor formation of diol by-products from alkene oxidation is observed. This simple system has excellent potential for scale-up, requires no storing or transport of stoichiometric oxidants, no heavy metals, and can be carried out with just water, sodium carbonate, hydrochloric acid, and an applied potential in a single cell. The electrolyte solution can be recycled and reused with no loss in activity.