Theoretical study on the dimerization reactions of silabenzenes

► The dimerization reactions of some silabenzenes were theoretically investigated. ► Most dimerization reactions occur via a concerted and synchronous way. ► [2 + 2] and [4 + 2] Reactions proceed much more easily than corresponding [4 + 4] reactions. ► Most [4 + 2] reactions occur more favorably than corresponding [4 + 4] reactions kinetically. ► Both electronic and steric hindrance effects of substituents affect activation barriers.