In conclusion, the Zn2(bim)4 film, a zinc-based MOF, was successfully synthesized with a thickness as thin as two unit-cells by using an ultra-dilute precursor solution and atomically smooth graphene substrate, overcoming challenges like homogeneous nucleation and substrate roughness. The approach allows for uniform, continuous films ideal for high-performance H2/CO2 separation, with thicknesses below 10 nm.