Nickel(0)-catalyzed cycloaddition copolymerization of CO2 with five ether diynes (RC=C(CH2)(l)O(CH2)(m)O(CH2)(l)C=CR, l = 2, m = 4, R = Me (1a), l = 2, m = 4, R = Et (1b), l = 2, m = 4, R = n-Pr (1c), l = 1, m = 4, R = Me (1d), and l = 1, m = 2, R = Et (1e)) was studied. The corresponding five poly(2-pyrone)s with molecular weights of 3300-29 100 were obtained in 45-88% yield in a THF/MeCN solvent at 110 degrees C. Ternary copolymerization of CO2 with equimolar amounts of 1a-c and EtC=C(CH2)(6)C=CEt (4) showed that an effect of three alkyl substituents (R = Me, Et, and n-Pr) on the copolymerizability of 1a-c with CO2 is mutually similar. The 1c/n-PrC=C(CH2)(10)C=C-n-Pr(6)/CO2 and 1e/4/CO2 ternary copolymerizations gave relative copolymerizabilities of 0.97 and 2.0, respectively, which indicated that an electron-withdrawing effect of an ether oxygen atom on the copolymerizability of a terminal C=C bond of a copolymer operates through one methylene group to increase the ether diyne copolymerizability, while such an electronic effect of the ether oxygen atom does not act through two methylene groups.