NTUniv-80 exhibits record-high volumetric and gravimetric acetylene (C2H2) uptakes of 210 cm3 (STP) g-1 and 227 cm3 (STP) cm-3 at 295 K and 1 atm, respectively. Grand canonical Monte Carlo (GCMC) simulation indicates that those remarkable C2H2 uptakes are attributed to the open Cu2+ sites and tailored cages.