Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials with tetrahedral networks similar to zeolites. ZIFs are synthesized using transition metals (Zn, Co) and imidazolate links. ZIFs exhibit unique structures determined by link–link interactions rather than structure directing agents used in zeolite synthesis. ZIFs have high thermal and chemical stability, and are highly functionalized with transition metal ions. The authors report the synthesis and characterization of two ZIFs, ZIF-95 and ZIF-100, with complex structures previously unknown in zeolites. These materials have large cages with up to 264 vertices and are constructed from up to 7,524 atoms. ZIF-100 can store 28 liters per liter of material at standard temperature and pressure. These materials are promising candidates for carbon dioxide capture and storage due to their high thermal and chemical stability, ease of fabrication, and selectivity for carbon dioxide. ZIF-95 and ZIF-100 have complex structures with large cages and high porosity. ZIF-100 has a cubic structure with a unit cell parameter of 71.9797 Å and a primitive cell volume of 1.86 × 10⁵ ų, making it one of the largest inorganic structures ever determined. ZIF-100 has a high surface area (780 m²/g) and micropore volume (0.37 cm³/g). ZIF-100 shows high selectivity for carbon dioxide, with one litre of ZIF-100 able to hold up to 28.2 litres of CO₂ at 273 K. ZIF-100 is more selective for CO₂ than BPL carbon, a widely used industrial adsorbent. ZIF-100 also shows complete reversibility in gas adsorption. ZIF-95 and ZIF-100 have high thermal stability, with thermal stability up to 500°C. ZIF-95 and ZIF-100 have high porosity and can store large amounts of gas. ZIF-100 has a large cage with 264 vertices and a 67.2 Å outer sphere diameter. ZIF-100 has a high selectivity for CO₂, with one litre of ZIF-100 able to hold up to 28.2 litres of CO₂ at 273 K. ZIF-100 is more selective for CO₂ than BPL carbon, a widely used industrial adsorbent. ZIF-100 also shows complete reversibility in gas adsorption. ZIF-95 and ZIF-100 have high thermal stability, with thermal stabilityZeolitic imidazolate frameworks (ZIFs) are porous crystalline materials with tetrahedral networks similar to zeolites. ZIFs are synthesized using transition metals (Zn, Co) and imidazolate links. ZIFs exhibit unique structures determined by link–link interactions rather than structure directing agents used in zeolite synthesis. ZIFs have high thermal and chemical stability, and are highly functionalized with transition metal ions. The authors report the synthesis and characterization of two ZIFs, ZIF-95 and ZIF-100, with complex structures previously unknown in zeolites. These materials have large cages with up to 264 vertices and are constructed from up to 7,524 atoms. ZIF-100 can store 28 liters per liter of material at standard temperature and pressure. These materials are promising candidates for carbon dioxide capture and storage due to their high thermal and chemical stability, ease of fabrication, and selectivity for carbon dioxide. ZIF-95 and ZIF-100 have complex structures with large cages and high porosity. ZIF-100 has a cubic structure with a unit cell parameter of 71.9797 Å and a primitive cell volume of 1.86 × 10⁵ ų, making it one of the largest inorganic structures ever determined. ZIF-100 has a high surface area (780 m²/g) and micropore volume (0.37 cm³/g). ZIF-100 shows high selectivity for carbon dioxide, with one litre of ZIF-100 able to hold up to 28.2 litres of CO₂ at 273 K. ZIF-100 is more selective for CO₂ than BPL carbon, a widely used industrial adsorbent. ZIF-100 also shows complete reversibility in gas adsorption. ZIF-95 and ZIF-100 have high thermal stability, with thermal stability up to 500°C. ZIF-95 and ZIF-100 have high porosity and can store large amounts of gas. ZIF-100 has a large cage with 264 vertices and a 67.2 Å outer sphere diameter. ZIF-100 has a high selectivity for CO₂, with one litre of ZIF-100 able to hold up to 28.2 litres of CO₂ at 273 K. ZIF-100 is more selective for CO₂ than BPL carbon, a widely used industrial adsorbent. ZIF-100 also shows complete reversibility in gas adsorption. ZIF-95 and ZIF-100 have high thermal stability, with thermal stability