Electrochemical oxidation of indole, C8NH7, in a non-aqueous medium, s
uch as a solution of LiClO4 or LiBF4, dissolved in acetonitrile, leads
to the formation of polyindole, an air stable conducting polymer that
exhibits electrochromic properties. The room temperature electrical c
onductivity, in the range 5 x 10(-3)-8 x 10(-2) S cm-1, depends slight
ly on the nature of the counterion.