A conjugated cyclocopolymer with a bulky substituents was synthesized via the MoCl5-catalyzed cyclopolymerization of diethyl dipropargylmalonate and 4,4'-bis[(tert-butyldiphenylsiloxy) methyl]1,6-heptadiyne. The chemical structure of polymer was characterized by NMR (H-1-,C-13-), IR, and UV-visible spectroscopies to have a conjugated backbone system with the designed substituents. The polymer showed characteristic UV-visible absorption band and absorption maximum value of 507 nm. Photoluminescence spectrum exhibited maximum peak at 594 nm, which corresponds to the photon energy of 2.09 eV. Band gap of cyclic copolymer was 2.01 eV.