(Z)-1-Methoxy-4-phenyl-1-buten-3-yne was polymerized over NbCl5- or TaCl5-based catalysts followed by pyrolysis to obtain graphite-like pyropolymers. The brown metthesis polymer, poly[(Z)-1-methoxy-4-phenyl-1-buten-3-yne] , has the structure of a fully conjugated backbone and was converted into black polyacene-based polymer on pyrolysis. The metathesis polymerization is influenced by substituents directly attached to the acetylene moiety. The structure of polymers is also influenced by oxygen. The polymers were characterized by elemental analysis, GPC, FT-IR, TGA, NMR, laser-Raman, X-ray diffraction, and SEM studies.