In this article some of the most important examples from the major classes
of organic electrochromic materials, namely the 1,1'-disubstituted-4,3'-bip
yridilium salts (the 'viologens'), conducting polymers, metallopolymers and
metallophthalocyanines are reviewed. Examples of their use in both a comme
rcial and several prototype electrochromic devices are given. (C) 1999 Else
vier Science Ltd. All rights reserved.