Abstract A supramolecular engineering approach has been developed for a novel family of N-salicylidene aniline derivatives to control their thermo-and photochromic behaviours. Hsaltrz, Habs, Hsalphen, Hsaltz and Ksaltz are versatile molecules built from N- heterocycles, which drive the molecular arrangement to form a controlled crystal packing with predesigned optical properties. A complete structural, optical and computational ...