UiO-66-NH2, formed by the coordination of hexanuclear zirconium-oxo cluster and 2-aminoterephthalate (BDC-NH2), possesses a cubic structure with a composition of Zr6O6(BDC-NH2)6. It has been reported that crystallinity can be enhanced with modulators such as hydrochloric acid, benzoic acid, 36 formic acid, 37 and acetic acid. Achieving 2D films of UiO-66-NH2 is particularly challenging due to the isotropic bond strength, which makes it difficult to synthesize anisotropic UiO-66-NH2 directly. To address this, synthesis conditions were modulated by screening different amounts of acetic acid as modulator to improve crystallinity, various metal and ligand concentrations, metal-to-ligand ratio, and the pH. Importantly, water was used as a solvent, keeping sustainability in mind. Atomically smooth graphitic substrates were used to promote in-plane growth. To form a thin film, substrates were immersed vertically halfway into the synthesis solution (Figure ), ensuring a distinct interface between the substrate and thin film. The film near the interface was then characterized by scanning electron microscopy (SEM) or atomic force microscopy (AFM). These experiments allowed to screen conditions for the successful growth of a thin film. Precursor concentration exceeding 1 mM and pH higher than 3.5 led to the deposition of aggregated particles instead of uniform film (Figure ). An increase in the ligand-to-metal ratio in the range of 8-10 accelerated undesired homogeneous nucleation in the bulk solution, resulting in rapid precipitation within 10 min and deposition of particles (Figure ).