ConstructingThree-Dimensional Covalent Organic Frameworkwith aea Topology and Flattened Spherical Cages

Constructing three-dimensional (3D) covalent organic frameworks (COFs) with novel topologies is one of the most effective strategies to enhance the diversity and complexity of crystalline organic porous materials. Herein, we have designed and synthesized a 3D COF (3D-OLC-aea-COF, OLC = Ordos Laboratory China) with an unprecedented <b>aea</b> topology, condensed from the 12-connected building units (triptycene-12-aldehyde) and the planar 3-connected building units. Structural simulations and high-resolution transmission electron microscopy successfully determined the crystal structure. Interestingly, the unique connection between two precursors creates novel cages with large cavities and small windows within the framework, which will likely bring valuable implications for guest molecular storage and nanoreactors. Notably, huge intrinsic free volume (IFV) of triptycene and the periodic arrangement of cages endowed 3D-OLC-aea-COF with excellent CO₂ capture capability. This work not only enhances the topological diversity and structural complexity of 3D COFs based on high-connectivity building units (≥8) but also provides inspiration for designing targeted materials through structure–activity relationships.