Two-dimensional metal-organic frameworks show increasing research attention due to their unique properties including tunable thickness, simple packing into a film and membrane, and high surface-to-volume atom ratios. A bottom-up synthesis strategy using cetyltrimethylammonium bromide for the synthesis of copper-benzenedicarboxylate (Cu(BDC)) nanosheets is reported. The method offers the synthesis of hierarchical porous Cu(BDC) lamellae with micrometer lateral dimensions, and nanometer thickness (100–150 nm). Electron microscope (scanning and transmission), and N2 adsorption isotherms confirm the formation of lamellae Cu(BDC) with mesopore size of 5–80 nm. The material has thermal stability up to 400 °C with good chemical stability in several organic solvents. However, the material transforms to another phase (Cu(BDC)(H2O)2) when soaked in water and alcohols. The transformation reduces crystal size and offers the formation of hydrogen bond resulting in an increase in the sorption of CO2 by ~10% compared to the pristine material Cu(BDC).