Well-defined model compounds of poly(N-phenyl-I ,4-phenyleneamine) (2), the dimer 5, the trimer 6 and the tetramer 7, were prepared by stepwise synthesis. Cyclic voltammetry and the mass spectra demonstrate the high stability of the radical cations from the model compounds. The UV spectra show that there is some conjugation through the lone electron pair at the nitrogen atom, but the amount of conjugation is rather small. Oligo(N-phenyl-I ,4-phenyleneamine) (2) with an average degree of polymerization of 10 was prepared by metalation of N,hr-diphenyl-l,4-phenylenediamine and subsequent reaction with 1,4-diiodobenzene. 0 1992, Huthig & Wepf Verlag, Basel CCC 0025-1 16X/92/$05.00