AbstractThe family of cyclic permethylpolysilanes, [(CH3)2Si]n, has been synthesized. Compounds in whichn= 5, 6 and 7 undergo reduction at low temperatures to form anion‐radicals. The five‐ and six‐membered rings give the parent anion‐radicals [(CH3)2Si]5− and [(CH3)2Si]6− when reduced electrolytically, but all three compounds give [(CH3)2Si]5− when reduced with alkali metals. The ESR spectra of the anion‐radicals show that the unpaired electron contacts all of the methyl protons equally, and so is fully delocalized over all the silicon atoms in the ring. The permethylpolysilanes have electron affinities similar to that of benzene; the ease of reduction is in the order [(CH3)2Si]5>benzene>[(CH3)2Si]6. These findings suggest that electron mobility and delocalization is not limited to “conjugated” molecules but can also be observed in systems not normally considered as “unsaturated.” Implications for the design of organic conducting ele