Mechanochemical synthesis is an attractive preparative method that combines a green approach with versatility, efficiency, and rapidity of reaction. However, it often yields microcrystalline materials, and their small crystal size is a major hindrance to structure elucidation with conventional single-crystal or powder X-ray diffraction methods. This work presents the novel approach of combining mechanochemistry with electron diffraction techniques to elucidate the crystal structure of metal–organic compounds of zinc­(II) and copper­(II) with 2,6-pyridinedicarboxylic acid and 4,4′-bipyridine.

The dynamic behavior of supramolecular organic frameworks (SOFs) based on the rigid tetra‐4‐(4‐pyridyl)phenylmethane (TPPM) organic tecton has been elucidated through 3D electron diffraction, X‐ray powder diffraction and differential scanning calorimetry (DSC) analysis. The SOF undergoes a reversible single‐crystal‐to‐single‐crystal transformation when exposed to vapours of selected organic solvents, moving from a closed structure with isolated small voids to an expanded structure with solvated channels along the b axis. The observed selectivity is dictated by the fitting of the guest in the expanded SOF, following the degree of packing coefficient. The effect of solvent uptake on TPPM solid‐state fluorescence was investigated, evidencing a significant variation in the emission profile only in the presence of chloroform.