We wish to show in this paper new developments and new applications of the pyrrole copolymerization process allowing the addressing of pyrrole-modified biomolecules on microelectrode arrays. Two main developments are described: the first one concerns the development of multiplexed silicon chips bearing 128 microelectrodes instead of 48 for the passive chips. The second one deals with new applications of this grafting process concerning not only DNA chips but peptide chips too. In this way, copolymerization of pyrrole peptides on the chip (leading to peptide chip) and their immunological detection is illustrated. This technology shows a high dimensional resolution and a real versatility.