Whilst imines 81 and boronic esters 82 are some of the most commonly used dynamic covalent systems, various others have been reported. These include the condensation between resorcinol and dialdehydes forming noria (26) and oligoresorcinarene macrocycles, 84 alkyne metathesis, and formation of disulfides 86 and boroxines (Fig. ). Orthogonal dynamic covalent linkages have also been used in concert, including imines and boronic esters, and imines and alkynes. Using these chemistries, and through careful design of building blocks, impressive architectures have been realised, including a 5.3 nm Tet 12 Di 24 cuboctahedron assembled from a porphyrin tetramine and a dialdehyde. Although often characterised and studied in the solid-state as porous materials, 91 POCs are usually solution processable and have been used as components of porous liquids, 92 and can be engineered to have sufficiently low melting points to render them as neat liquids. The conditions under which POCs are stable will depend on the nature of the structure and DCC being used. Imines, for example, are generally susceptible to hydrolysis, although examples of hydrolytically stable systems are known; 94 structural tailoring has been used to enhance the stability of imine-based cages, or alternatively exploitation of keto-enol tautomerisation 96 or use of more robust hydrazones provide access to more stable analogous systems. For some systems this is less of a consideration. Alkynes, for example, require a catalyst for metathesis; otherwise, they remain kinetically stable under a wide range of conditions. The dynamic nature of these organic cages can be exploited for stimuliresponsive transformations, such as the exchange of components in cage-to-cage conversions. With a wide range of dynamic covalent chemistries to choose from, and with a choice of building blocks only limited by synthetic accessibility, dynamic covalent cages are a versatile class of molecular capsules. Systems can be designed of different geometries and sizes with precise control over pore and cavity size 100 and solubility, 101 and covalent linkages chosen to be stable under a set of required conditions. Indeed, orthogonal DCCs can be combined to enable bond cleavage at specific sites upon application of specific stimuli, making them suitable for developing stimuli-responsive architectures.