W(NO)(2)(O2CR)(2) - Lewis acid (LA) catalysts (LA = TiCl4, SnCl4; R = -CH(C2H5)(CH2)(3)CH3) induce substituted acetylenes (phenylacetylene, propargyl ether, 1,6-heptadiyne, diphenylacetylene) to polymerize or oligomerize. Their catalytic ability strongly depends on the Lewis acid and solvent. The polymerization reactions of phenylacetylene always accompany the cycolotrimerization reactions. In the system with TiCl4 in CH2Cl2 the yield of polymer equals to 56% at 80% conversion of a monomer. However, in the system with SnCl4 in benzene, 42% cyclotrimers arise at 57% conversion of phenylacetylene. The mechanism of these reactions as well as the structure of the obtained polymers were determined.