Two-dimensional (2D) hierarchically porous metal–organic framework (MOF) nanoarchitectures with tailorable meso-/macropores hold great promise for boosting performance in heterogeneous catalysis. However, achieving the general synthesis of 2D MOF nanosheets with controllable hierarchical porosity and thickness remains challenging. Herein, we present a "hard" emulsion-induced interface super-assembly strategy for preparing 2D hierarchically porous UiO-66-NH₂ nanosheets with highly accessible pores, tunable meso-/macropore sizes, and adjustable thicknesses. Importantly, it can be extended to prepare other 2D hierarchically porous MOF nanosheets with different compositions and structures. Benefiting from fast mass transfer and highly accessible active sites, the 2D hierarchically porous UiO-66-NH₂ nanosheets deliver a fabulous catalytic yield of ~96% in the CO₂ cycloaddition reaction, far exceeding the yield of ~29% achieved using UiO-66-NH₂ microporous crystals.