A novel and eco-friendly electrochemical activation of trifluoromethyl thianthrenium triflate (TT–CF3+OTf−) for trifluoromethylation of imidazole-fused heteroaromatic compounds was established. This method involves the direct electrolysis of TT–CF3+OTf− without the requirement of external oxidants or catalysts, aligning with the principles of green chemistry. A wide range of imidazole-fused heteroaromatic compounds including imidazo[1,2-a]pyridines and benzo[d]imidazo[2,1-b]thiazoles have been successfully trifluoromethylated using this technique, exhibiting excellent compatibility with various functional groups and a broad substrate scope. Moreover, the method’s applicability for one-pot sequential reactions enables the reduction of waste and resource consumption by eliminating the need for intermediate purification steps.