Dynamic Covalent Radical Recombination for the Assembly of Tuneable Responsive Porous Organic Cages

The construction of discrete organic cages via radical recombination offers a powerful yet underexplored route toward stimuli-responsive, C─C-linked molecular architectures. Here, we introduce aryldicyanomethyl radical dynamic covalent chemistry as a general strategy for the controlled assembly of porous organic cages. Systematic variation of a single substituent governs both radical and σ-bond stability as well as the resulting cage geometry, enabling precise, substituent-dependent control over cage topology and responsiveness. A thiophenoxy-substituted monomer S selectively affords a discrete Tri² dimer in 99% yield, whereas the N-methylaniline-substituted analogue N forms the tetrahedral Tri⁴ tetramer in 83% yield. N⁴ possesses permanent porosity and pronounced selectivity for CO₂ and H₂ over CH₄ and N₂, as confirmed by gas sorption experiments, arising from narrow pore apertures and strong host-guest interactions. Both cages display reversible mechano- and thermochromic behaviour. Moreover, the combination of a highly dynamic bond formation process with three-dimensional preorganisation of the cage enables efficient self-healing, which is markedly accelerated upon exposure to THF vapour. Collectively, these results establish radical recombination as an unexplored dynamic covalent motif for the synthesis of responsive organic cage architectures, enabling substituent-dependent fine-tuning of topology, stability, and material function through simple substituent modification.