The great variety of colour contrast achieved with electronically cond
ucting polymers is the most significant characteristic of this class o
f ion-insertion organic materials. The performance of selected electro
chromic devices based on electronically conducting polymers, with orga
nic or inorganic materials as optically passive or electrochromic in c
omplementary mode counter-electrodes, is reported and the advantages a
nd drawbacks of each system discussed.