Sustainable hydrogen production requires large amounts of treated freshwater and precious metals. Direct electrolysis of seawater without additional electrolytes can be a practical approach to address these limitations, however, it usually suffers from kinetically favored chlorine evolution reaction (CER), which is detrimental to an electrolysis system. We report that organocatalytic amphiphilic diamines play a crucial role in preventing the generation of chlorine gas. The feasibility of direct seawater electrolysis was demonstrated with pH-responsive organic amines, which can self-assemble under neutral and acidic conditions. Electrochemical analysis of our electrolysis in saline solutions revealed that (electro)chemical stability of amphiphilic diamines was responsible for preventing CER and hypochlorite formation. Our findings may have significant implications for the chemical industry and energy sectors as the world transitions towards renewable energy sources.