ZIFs materials (ZIF-7, ZIF-8, ZIF-9, and ZIF-67) were used as precursors for the synthesis of metal-based catalysts embedded into N-doped nanoporous carbons via carbonization at elevated temperature for cycloaddition reaction (Table ) . Among the carbonized materials, carbonized ZIF-9 at 600 °C (denoted as C600-ZIF-9) under an inert gas (Ar) showed the highest catalytic activity (yield of 90%) at 80 o C under 0.6 MPa of CO2 . The increased activity could be due to the uniformly distributed acidic and basic sites of partly oxidized cobalt nanoparticles and nitrogenous species . ZnO nanoparticles encapsulated into N-doped porous carbon were synthesized via the carbonization of ZIF-8 followed by oxidation treatment with sodium hypochlorite (NaClO) . The oxidation of the carbonized materials offered several oxygencontaining functional groups such as carboxyl, lactone, and alkoxy. ZnO@NPC-Ox-700 (NPC: Ndoped porous carbon, Ox oxidized, 700 refers to carbonized temperature ( o )) exhibited the highest catalytic conversion, selectivity, and recyclability for CO2 cycloaddition . Bimetallic ZIF containing Co and Zn can be used to synthesize Zn/Co@C magnetic nanoparticles via carbonization process at 900 o C, denoted as N-doped magnetic porous carbon (NPC-900) . NPC-900 is a recyclable catalyst with a simple separation procedure via an external magnet . ZIF-L-derived catalyst offered high catalytic activities for CO2 cycloaddition with 83% yield under mild conditions (70 °C and 0.1 MPa CO2) .