The practical utilization of covalent organic frameworks (COFs) with manipulation at the atomic and molecular scale often demands their assembly on the nano-, meso-, and macroscale with precise control. Consequently, synthetic approaches that establish the ability to control the nucleation and growth of COF crystallites and their self-assembly to desired COF nanomorphologies have drawn substantial attention from researchers. On the basis of the dimensionality of the COF morphologies, we can categorize them into zero- (0-D), one- (1-D), two- (2-D), and three-dimensional (3-D) nanomorphologies. In this perspective, we summarize the reported synthetic strategies that enable precise control of the COF nanomorphologies’ size, shape, and dimensionality and reveal the impact of the dimensionalities in their physicochemical properties and applications. The aim is to establish a synergistic optimization of the morphological dimensionality while keeping the micro- or mesoporosity, crystallinity, and chemical functionalities of the COFs in perspective. A detailed knowledge along the way should help us to enrich the performance of COFs in a variety of applications like catalysis, separation, sensing, drug delivery, energy storage, etc. We have discussed the interlinking between the COF nanomorphologies via the transmutation of the dimensionalities. Such dimensionality transmutation could lead to variation in their properties during the transition. Finally, the concept of constructing COF superstructures through the combination of two or more COF nanomorphologies has been explored, and it could bring up opportunities for developing next-generation innovative materials for multidisciplinary applications.

Heterogeneous catalysis in water has not been explored beyond certain advantages like recyclability and recovery of the catalysts from the reaction medium. In doing so, they often fail to address other authentic pitfalls of homogeneous catalysis. Moreover, poor yield, extremely low selectivity, and active catalytic sites' deactivation further underrate the heterogeneous catalysis in water. On the other hand, most of the synthetically useful homogeneous catalysts are either water intolerant or remain catalytically inactive in water. Considering these facts, we have rationally designed and synthesized solution dispersible porous covalent organic framework (COF) nano-spheres to utilize their distinctive morphology and dispersibility to bridge between homogeneous and heterogeneous catalysis. The success has further been extended in fabricating catalyst immobilized COF thin-lms via covalent self-assembly for the very rst time. We have used these catalyst immobilized COF thin-lms to develop a general methodology for the C-H functionalization of organic substrates in water. This unique covalent self-assembly occurs through the protrusion of the bers/threads at the interface of two nano-spheres, transmuting the catalytic spheres into lms without any leaching of catalyst molecules, which was hitherto unheard of. The catalyst immobilized porous COF thin-lms' chemical functionality and hydrophobic environment stabilizes the high valent transient active oxoiron(V) intermediate in water and restricts the active catalytic site's deactivation. An elevated catalytic yield and high selectivity (3°:2°) have been achieved in open-air conditions at room temperature, accompanying the elemental feature of heterogeneous catalysis, i.e., the recyclability. These COF lms functionalized the unactivated C-H bonds in water with a high catalytic yield (45-99%) and with a high degree of selectivity (cis:trans=155:1; 3°:2°=257:1 in case of cis-1,2dimethylcyclohexane). To establish the "practical implementation" of this approach, we conducted the in ow catalysis (Turnover Number = 355±5) using catalyst immobilized COF lms fabricated on a macroporous polymeric support.

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