Several environmentally benign eutectic-based ionic liquids (ILs) were developed as novel homogeneous catalysts for efficient conversion of carbon dioxide to cyclic carbonates. Propylene oxide (PO) was selected as a benchmark substrate to optimize the catalytic activity, and on account of the catalytic cooperativity between the cation and anion in the [urea-Zn]I-2 catalyst, excellent yield (95%) and selectivity (98%) to propylene carbonate (PC) was obtained under the optimized reaction conditions of 120 degrees C and 1.5 MPa for 3.0 h in the absence of cocatalyst and solvent. Also [urea-Zn]I-2 was proved to be an efficient and versatile catalyst, and could realize catalytic conversion of CO2 with various epoxides. Moreover, the synergistic reaction mechanism involving cation structure and halogen anion for CO2 conversion was proposed, and the eutectic-based ILs were easily recyclable with high activity. The eutectic-based ILs that possessing low cost, moisture-stability, facile synthesis and efficiently bifunctional properties reported herein displayed the exceptionally outstanding features for efficient conversion of CO2 to cyclic carbonates. (C) 2015 Elsevier B.V. All rights reserved.