The cis-1,4 selective copolymerizations of butadiene (BD) with naked polar methylthio-and p-tolylthio-functionalized alpha-olefins have been investigated by using the thiophene-fused cyclopentadienyl scandium complex. The substitutes of the alpha-olefins are critical to govern the performances of the copolymerizations and the chain structures of the resultant copolymers. The copolymerization of polar 4-methylthio-1-butene (MTB) and BD performs in dual high syndioselectivity and cis-1,4 selectivity. The incorporation of MTB varies from 65.6% to 100% much high than its loading fraction, indicating the privilege of polar MTB coordination-insertion; thus, blocky microstructure is afforded. On the contrary, the copolymerization of 4-(p-tolylthio)-1-butene (pTTB) and BD is more controllable to display high activity and syndioselectivity albeit with slightly lowered cis 1,4 selectivity. The afforded copolymers possess high molecular weights close to the theoretical ones, and pTTB insertion could be precisely controlled by monomer feed ratio, suggesting the random microstructure. The possible mechanisms of copolymerizations are proposed.