showed that the exfoliated MONs -the GUF-14 hns phase -induced a much higher conversion towards the desired imine (78% by F NMR spectroscopy; isolated yield 71%) compared to both GUF-14 hxl (14%), Zr-EDB fcu (22%), and an uncatalysed control (17%; Table , entries 1-4). It would be expected that the GUF-14 hns and hxl phases, with 6-connected Zr6 SBUs and potentially half of all carboxylate coordination sites available for catalysis, show higher activity than the Zr-EDB fcu phase, where the only feasible equivalent active sites would be at particle surfaces or missing linker defects around the 12-connected Zr6 SBU. The much lower conversion observed for the bulk GUF-14 hxl phase in comparison to the GUF-14 hns nanosheets demonstrates that reagent accessibility is key.