Dr. Umemoto's research is briefly described and his achievements are chronologically summarized, which include electrophilic perfluoroalkylating agents (FITS), N-fluoropyridinium salts as power and structure-variable electrophilic fluorinating agents and application to battery materials, and O-, S-, Se-, and Te- trifluoromethyled dibenzoheterocyclic onium salts as power-variable electrophilic trifluoromethylating agents.