A compound comprises a polymeric chain with a repeat unit repeated more than 5 times. The repeat unit comprises conjugated first and second cyclic groups and a plurality of side groups each bonded to one of the cyclic groups. A side group bonded to the first cyclic group is an electron donor and a side group bonded to the second cyclic group is an electron acceptor, such that the compound is switchable between first and second electrical conductive states by application of an electric field to the compound. At least one of the side groups is selected so that the compound is soluble in an organic solvent. The compound may be used in films, memory cells, or electronic devices. A layer of the compound may be formed on a surface by dissolving the compound in an organic solvent, applying the solution to the surface, and then removing the solvent.