Deselenation of a 1,3,5-triselena-2.4.6-tristibane bearing 2.4.6-tris[bis(trimethylsilyl)methyl]phenyl (denoted as Tbt) groups in the presence of 1,3-butadienes resulted in the formation of the corresponding [1 + 4]-cycloadducts of a sterically hindered stibinidene (Tbt-Sb:), a monovalent species of antimony. Thermal generation of the stibinidene from the stibolene derivatives via retro [1 + 4]-cycloaddition reaction was suggested by the diene-exchange reaction in thermolysis of the adducts in the presence of another butadiene derivative.