Herein, we report the first non-vdW 2D MOF in the form of 2D UiO-66-NH2 film by developing conditions leading to anisotropic 2D growth. Briefly, the composition of the precursor solution was screened to develop growth conditions that delay homogeneous nucleation of UiO-66-NH2 in the bulk solution, promote in-plane growth of 2D nuclei, and slow out-of-plane growth. This was further facilitated by the use of atomically smooth graphitic substrates. A crystallographic registry between the graphene superstructure and the 2D lattice of UiO-66 along the a-out-of-plane direction was observed. The thickness of the film could be tuned from 0.5 to 2 unit cells. Pinhole-free sub-10-nm-thick films could be prepared, evident from K + /Mg 2+ selectivity. Thanks to the high stability of the UiO-66 framework, unit-cell-thick films were stable in 0.1 M salt solutions for more than one month. The chemistry for the synthesis of the film is green (water as opposed to organic solvent) and user-friendly involving room temperature synthesis reaction time that is only a few minutes.