During the MOF synthesis, the modulator binds to the Zr6 nodes to produce crystals with lower connectivity, and consequently with larger size due to slower nucleation and crystal growth kinetics. Although this is a reliable way to produce MOF particles with tunable particle sizes, it is at the expense of control over the number of defects (Figure ). The MIDA strategy therefore prevents the synthesis of highly defective and ultra-small nanoMOFs which are optimal candidates for catalysis. Notably, numerous reports have pointed out the importance of overcoming diffusion barriers, with MOF catalysed reactions mainly taking place on the outer surface of the particles. This is the case particularly when the size of the substrate is comparable to the aperture size of the MOF's pores. Although the substrates may diffuse inside the MOF framework, the desorption of the resulting products can be hampered by kinetic limitations. Relying on exfoliated high aspect ratio 2D porous nanosheets is an appealing alternative strategy to overcome these limitations. However, these nanomaterials are usually more challenging to prepare (or exfoliate) and/or exhibit usually a reduced stability compared with their related 3D counterparts. Therefore, developing new routes to both downsize robust nanoMOFs whilst ensuring a high defect content to address challenging catalytic reactions is a hot topic. The MIDA approach, which is usually carried out in DMF at high temperature and pressure, has mainly been explored with UiO-66 with missing linker defect content of ca. 10-20%. However, it has not been extended to the functionalized derivatives and thus, the full potential of this defective nanoMOFs family has not been exploited so far. It is therefore required to develop new synthetic versatile strategies to maximize these defects while maintaining reasonable thermal/chemical stability of the nanoMOFs to meet the demands of applications.