Two new mesoporous metal-organic frameworks (DUT-75 and DUT-76) with exceptional ethene uptake were obtained using carbazole dicarboxylate based metal-organic polyhedra as supermolecular building blocks. The compounds have a total pore volume of 1.84 and 3.25 cm³ g^-1 and a specific BET surface area of 4081 and 6344 m² g^-1, respectively, and high gas uptake at room temperature and high pressure.