Environment-benign trifluoromethylselenolation of alkyl halides, electron-deficient aryl halides, diaryliodonium triflates, aryldiazonium tetrafluoroborates, and α-diazo carbonyls with the readily accessible [Me4N][SeCF3] salt is described. A large number of structurally diversified substrates, previously trifluoromethylselenolated by metal-SeCF3 complex or under metal-mediated catalysis at elevated temperatures, were smoothly converted in this reaction at room temperature or −40 °C to room temperature without using any catalyst or additive. Yields of the reactions were comparative to or even higher than those of the early reports employing transition metal catalysts. Compared to the known means, advantages of this method include simplicity, sustainability, high speed, low reaction temperatures, mild reaction conditions, a wide range of substrates, and good functional group tolerance. This catalyst- and additive-free protocol allows a mild and straightforward synthesis of various trifluoromethyl selenoeth...