The syntheses of a tetraazamacrocycle functionalized at nitrogen with a pendant 3-thiophene, 1 -[2-(3thienyl)ethyl]-l,4,8,1 I-tetraazacyclotetradecane (cyclamN-CH2CH2-thiophene), and its complexes with Nil1 and Cull, are described. Electro-oxidation of the pure Nil1 complex in acetonitrile electrolytes afforded only soluble oligomers. Novel conducting polymer-modified electrodes were fabricated, however, by electrocopolymerization of the Nil' complex with 3-methylthiophene. These are unusual in that both the metal centre [Ni1l-NiI1l at +I . I 5 V (saturated calomel electrode)] and the conducting polymer backbone show stable, reversible redox behaviour, with no apparent oxidative degradation of the poly(thiophene) backbone. The Ni1I-Ni1l1 redox behaviour appears unaffected by incorporation into the conducting polymer matrix. However, the NilI-Nil wave, observed at -1.40 V in solution, is entirely suppressed in the polymer, which at that potential is an electronic insulator.