Silole-based pi-conjugated compounds and their derivatives have been actively studied as promising electroluminescent materials because of their unique electronic structure (low-lying LUMO level), formed by sigma*-pi* conjugation. This article summarizes recent progress in the synthesis of silole derivatives and the applications as both emitter and electron-transport materials, respectively from 1, 1, 2, 3, 4, 5-substituted siloles, silicon-bridged stilbene, dithienosilole, spiro-silole derivatives. This article explains how the silicon tunes up the electronic structure of the heterocyclic systems. The influence of molecular structures achieved by changing the substitutes on the electronic properties of silole derivatives is discussed in detail. The future research direction of silole derivatives is also mentioned.