Symmetry-Encoded [6 + 12] Octahedral Organic Cages Enabled by Retrospective Design

Octahedral [6 + 12] porous organic cages (POCs) remain largely unexplored owing to stringent geometric requirements imposed on tetratopic building units and the inherent challenges associated with growing diffraction-quality single crystals of highly connected cage architectures. Here, we report a retrospective design strategy for octahedral cages using a dibenzo[a,e]cyclooctene (DBCOT)-based nonaromatic tetratopic vertex that satisfies the required angular geometry. Coupling these vertices with linear ditopic linkers via imine condensation affords a series of isoreticular [6 + 12] cages. Their intrinsic insolubility precludes conventional crystallization and solution-phase characterization. Thermodynamically controlled in situ crystallization using polar aromatic solvents, Lewis acid catalysis, and slow cooling affords single crystals up to ∼ 1 mm and enables direct structure determination using a laboratory X-ray diffractometer. Directional edge-to-edge packing of the cages generates hierarchical pore networks that remain accessible after activation. Notably, this packing propagates the octahedral molecular geometry across length scales into the macroscopic octahedral crystal habit, revealing molecular-to-crystal shape transference. These findings establish a general platform for designing structurally rare higher-connectivity cages with geometry-programmed assembly across length scales.