A novel type of catalysts useful in the anionic polymerization processes is demonstrated. Alkali metal ion pairs, e.g. K+ crown ether, K- discovered first by Dye and Edwards were modified and used as catalysts in the polymerization of isoprene. The reaction mechanism including two-electron transfer to monomer and formation of a carbanion is discussed. The novel type of anionic polymerization yields polyisoprene with well-defined properties.