Covalent organic framework monoliths: structures, applications and biomimetic opportunities

This review summarizes the fundamental structural features, synthetic methodologies and physicochemical properties of COFs, and discusses the key limitations associated with their powder-based form. Recent progress in the development of monolithic COF materials - including membranes, foams, 3D printed monoliths and aerogels - is critically analyzed in the context of multiscale architecture, mass transport and mechanical robustness. These examples demonstrate that macroscopic structuring across multiple length scales is essential for translating intrinsic framework properties into device-relevant performance. Finally, emerging biomimetic concepts in COF research are discussed, with a focus on bioinspired architectures and monolithic materials that emulate natural hierarchical systems. Current challenges related to scalability, structural control and long-term stability are assessed and future prospects for biomimetic COF monoliths are outlined. This review aims to provide a framework for the rational design of functional COF materials, bridging molecular precision and macroscopic form.