A series of diarylethenes with substituents of different size and chemical nature was synthesised
showing that beside some intermolecular interactions involving the central diarylethene core, lateral
groups clearly play a key role in the crystal packing arrangements. These structural features were further
analyzed in relation to the thermal data obtained by differential scanning calorimetry (DSC) and
monitored using FT-IR spectroscopy, thus providing a rationalization of the observed thermal transitions
processes. The role of van der Waals interactions is crucial in driving crystal packing formation towards
loosely packed arrangements characterized by large hydrophobic contact areas. Interestingly, some
functional substituents favour an amorphous state after thermal treatment, a peculiar feature that can be
exploited to design uniform photochromic layers
