Herein we report the development of a novel binary catalytic system for the addition of CO₂ to epoxides based on zinc iodide and an imidazolium salt. The influence of the nature of the imidazolium ion and the anion has been studied in a test reaction. The optimized system exhibits excellent activity and selectivity. Furthermore, the reaction can be performed under very mild (30 °C) and solvent free conditions yielding the desired cyclic carbonates in up to 99%.