The functionalization of electroactive polymers (electroconducting conjugated and redox-type polymers) by monocyclic and acyclic polyether groups is reviewed. In general, materials were chemically or electrochemically deposited as a, film onto electrode surfaces from the oxidation of the substituted monomers. The ability of such structures for complexing cations could be evidenced from the modification of their electrochemical and optical properties. In the class of the conjugated polymers, functionalized polythiophenes and polyphenylenes led to numerous representative examples showing they were suited for the building of cationresponsive electrodes. Accordingly, some of these polymers were successfully used for the recognition and the extraction of a large variety of cations including alkali, heavy and precious metal cations. Different, strategies were developed not only to enhance the affinity between the ligand and the cation, but also to obtain chemically reversible and selective ionic sensors. (C) 1998 Elsevier Science S.A. All rights reserved.