A new microporous metal-organic framework Cu(2)(EBTC)(H(2)O)(2) x xG (EBTC = 1,1'-ethynebenzene-3,3',5,5'-tetracarboxylate; G = guest molecule) was rationally designed with a NbO net, exhibiting significantly high acetylene storage of 252 and 160 cm(3) g(-1) at 273 and 295 K under 1 bar, respectively.