New PPV derivatives containing cross-linkable acetylene groups, poly(2-methoxy-5-propagyloxy-1,4-phenylevinylene) (PMPPV) and its PPV copolymers were synthesized through the soluble precursor polymers. PMPPV film was higly cross-linked and lost its properties of a conjugated polymer at over 200 degrees C. The electrical conductivities of PMPPV films were measured by four probe method after FeCl3 doping. The undrawn and 10 times drawn PMPPV films showed thier electrical conductivities of 1.5 x 10(-1) and 92 S/cm, respectively. Conjugation length of poly(PV-co-MPPV) was controlled by changing the PMPPV monomer feed ratio.