The cyclopolymerization of 1,6-heptadiene derivatives catalyzed by the Ni- and Pd-diimine complexes and regio- and stereoselectivity of the reaction was reported. Four signals at 139.4, 140.3, 152.3, and 154.0 were assigned to the aromatic carbons of the five-membered ring, while the remaining quaternary carbon exhibited a single signal at 51.0. The results show that each carbon signal of the cyclopentane ring of the polymer obtained appears as almost single peak, which indicate high degree of controlled tacticity of the obtained polymer. The Pd-complex-catalyzed reaction is found to produce the polymer with five-membered rings through intermolecular 2,1-insertion of a C-C double bond. The structural changes of the complexes facilitate coordination of the monomer with opposite direction to that of the intermediate of polymerization and promotes 2,1-insertion and formation of the five-membered ring.