The combination of N-fluorobenzenesulfonimide (NFSI) with diselenides allowed the rapid decarboxylative tri- or tetrafunctionalization of alkynyl carboxylic acids under catalyst-free room-temperature conditions. This reaction offers a novel and facile route to polyseleno-substituted enamines, which employs NFSI not only as a useful oxidant but also as an efficient amination reagent, displays a broad substrate scope and results in good to excellent yields. An electrophilic mechanism is proposed for the transformation.