Abstract Aiming at gaining more insight into the high catalytic activity of ZnCl 2/[BMIM] Cl co- catalysts and elucidating the origination about the product enantioselectivity for the coupling reaction of CO 2 with epoxides, a mechanistic study has been conducted by performing density functional theory calculations. The calculated results indicate a new stable complex [BMIM] ZnCl 3 is probably formed via the dissociation of the in situ generated [BMIM] 2 ...