<p>The formation of C–S bonds plays a pivotal role in the preparation of drug molecules and their intermediates. Utilizing an electrochemical method powered by renewable energy offers a sustainable pathway to produce organosulfur compounds but faces challenges, such as low Faradaic efficiency (&lt;6.8%) and production rate (&lt;10 µmol cm⁻² h⁻¹). Here we developed an efficient electrochemical approach to build C–S bonds and prepare a range of C–S species in high yield by coupling biomass oxidation with a sulfur-containing nucleophile using commercial catalysts. Taking methanol as a representative, we successfully synthesized hydroxymethanesulfonate, sulfoacetate and methanesulfonate. This system achieved a remarkable Faradaic efficiency of over 95% with a low current density below 10 mA cm⁻². At commercial current densities ranging from 100 to 1,000 mA cm⁻², the Faradaic efficiency remained consistently over 60% in a practical flow reactor with high production rates and stable operation over 50 h without significant voltage increases or yield decreases at 100 mA cm⁻². Four reaction pathways, with *CH₂O, *CH₃ and *HOCH₂CHO as key intermediates, have been identified to facilitate the C–S bond formation. This process can be extended to synthesize a wide range of organosulfur and organonitrogen compounds from diverse feedstocks, achieving impressive production rates. This approach is promising for the production of pharmaceuticals, textile chemicals and agrochemicals.</p><p></p>