Bis[bis(methylthio)lithiomethyl]dimethylsilane was generated from bis[bis(methylthio)methyl]dimethylsilane by deprotonation with t-BuLi in THF and allowed to react with various dichloro(poly)silanes to give the corresponding 4- to 7-membered polysilacarbacycles in moderate to good yields. The methylthio groups in the cyclized products were readily removed by radical reduction with Bu3SnH.