A method is provided for modifying a poly(arylene vinylene) or poly(heteroarylene vinylene) precursor polymer having dithiocarbamate moieties by reacting it with an acid and further optionally reacting the acid-modified polymer with a nucleophillic agent. Also provided are novel polymers and copolymers bearing nucleophillic side groups which are useful as components of electronic devices, e.g. in the form of thin layers.