Nineteen 12-, 15-, 18-, 24- and 30-membered, highly unsaturatedmacrocyclic silicohydrocarbons containing -SiCCSi-, (E)-SiCHCHSi- and -SiCH2CH2Si-fragments in the ring were synthesized by the reaction of Me2Si(CCMgBr)2 or BrMgCCMe2SiCCSiMe2CCMgBr with FMe2SiCH2CH2SiMe2F; (E)-FMe2SiCHCHSiMe2F or (E, E)-(ClMe2SiCHCH)2SiMe2; (E)-BrMgCCMe2Si-CHCHSiMe2CCMgBr or Me2Si(CCSiMe2CCMgBr)2 with (E