Multicomponent flexible organic crystals

Flexible organic crystals are emerging as a potential candidate for smart materials and have aroused great interest over the past decade. In view of multicomponent supramolecular synthesis with a distinct advantage over single-component approach on the control of molecular arrangements and physicochemical properties, we take note of various multicomponent flexible organic crystals in the range from organic co-crystals, supramolecular salts, solvates, doping organic crystals to solid solution crystals, showing a great diversity of supramolecular architectures such as one-dimensional columns, two-dimensional layer packing, and three-dimensional interlocked structures. Some of them serve as promising multifunctional materials with both flexibility and photoelectric properties such as fluorescence, optical waveguide, and ferroelectricity. In this review, we focus on the packing structures of multicomponent flexible organic crystals and their related mechanical properties, highlight typical research works, and point out the main possible directions that remain to be developed in this field. From the perspectives of crystal engineering and supramolecular chemistry, the flexible crystals outlined here should offer helpful information for further design and investigation on the elusive class of mechanically compliant crystalline compounds.