The syntheses and electropolymerisation reactions of several new active ester pyrrole derivatives are described. It is shown that the electropolymers can be modified in high yield by reaction with amine or alcohol functionalised molecules, that such films can be crosslinked or functionalised with pendant amine groups. that bilayer polymer films can be selectively modified and that the release of 2,4-dinitrophenol into solution from the corresponding active ester poly(pyrrole) provides a sensitive spectroscopic probe of polymer conversion.