Poly(2-methoxy-1,4-phenylenevinylene) (PMVP) and copolymers containing both unsubstituted (1,4-phenylenevinylene, PV) and 2-methoxy-1,4-phenylenevinylene (MPV) units were prepared in thin films from their water-soluble sulfonium salt precursor polymers. Drawn films (L/L0 = 6) of the PMPV homopolymer could be doped with 12 vapor and FeCl3 to give conductivities of 3,2 and 4,0 S . cm-1, respectively. The conductivity of FeCl3-doped copolymer films ranged from 10(0) to ca. 10(2) S . cm-1 depending on the composition. The third-order nonlinear susceptibility, chi(3), for the PMPV film was investigated by degenerate four-wave mixing technique using 400 femtosecond pulses at 602 nm. A relatively large chi(3) value (7,9 . 10(10) esu) with a subpicosecond response was observed.