ABSTRACT The miniaturization and integration of electronic/photonic devices demand precise control over light at the micro‐scale. However, achieving tailored optical anisotropy through intrinsic material design, rather than external components, remains a significant challenge. Herein, we report a general and programmable strategy for the growth of one‐dimensional organic crystals with precisely tunable asymmetric architectures via a spatially defined temperature gradient. By leveraging the competitive, facet‐dependent growth kinetics under a thermal bias, continuous and precise control over the structural asymmetry is achieved in single crystals, with a tunable morphological anisotropy ranging from 9% to 81%. The resulting asymmetric crystals exhibit a pronounced direction‐dependent optical response, yielding a photoluminescence intensity contrast ratio as high as 113.3, which scales directly with the degree of structural asymmetry. This work establishes a material‐based platform for applying direction‐dependent photonic properties directly into crystal morphology, paving the way for advanced organic photonic materials with built‐in anisotropy.
Ma et al. (Sat,) studied this question.