In the recent decade, the development and application of organocatalysis for CO2 transformation into useful chemicals have attracted much attention. Among these organocatalysts, Lewis base-CO2 adducts (LB-CO2) were found to be more efficient. The used Lewis base has great effect on the catalytic activity of its CO2 adduct. This review reports the recent progress in LB-CO2 adducts catalyzed the cyclization of CO2 with epoxides or aziridines to afford cyclic carbonates or oxazolidinones, the carboxylation of CO2 with propargylic alcohols to α-alkylidene cyclic carbonates, and the reduction of CO2 to methanol, formamides and methylamines, with the focus on the catalytic mechanism.