Self-assembly of particles into long-range, three-dimensional, ordered superstructures is crucial for the design of a variety of materials, including plasmonic sensing materials, energy or gas storage systems, catalysts and photonic crystals. Here, we have combined experimental and simulation data to show that truncated rhombic dodecahedral particles of the metal-organic framework (MOF) ZIF-8 can self-assemble into millimetre-sized superstructures with an underlying three-dimensional rhombohedral lattice that behave as photonic crystals. Those superstructures feature a photonic bandgap that can be tuned by controlling the size of the ZIF-8 particles and is also responsive to the adsorption of guest substances in the micropores of the ZIF-8 particles. In addition, superstructures with different lattices can also be assembled by tuning the truncation of ZIF-8 particles, or by using octahedral UiO-66 MOF particles instead. These well-ordered, sub-micrometre-sized superstructures might ultimately facilitate the design of three-dimensional photonic materials for applications in sensing.

The use of covalent organic frameworks (COFs) in practical applications demands shaping them into macroscopic objects,which remains challenging.Herein, we report asimple three-step method to produce COF aerogels,b ased on sol-gel transition, solvent-exchange,a nd supercritical CO 2 drying, in which 2D imine-based COF sheets link together to form hierarchical porous structures.T he resultant COF aerogel monoliths have extremely lowd ensities (ca. 0.02 gcm À3 ), high porosity (total porosity values of ca. 99 %), and mechanically behave as elastic materials under am oderate strain (< 25-35 %) but become plastic under greater strain. Moreover,these COF aerogels maintain the micro-and meso-porosity of their constituent COFs,and show excellent absorption capacity (e.g. toluene uptake:3 2gg À1 ), with high removal efficiency (ca. 99 %). The same three-step method can be used to create functional composites of these COF aerogels with nanomaterials.