Precision Synthesis of Organic Donor–Acceptor Mesocrystals With Diverse Morphologies: Unbranched, Branched, and Heterostructured Architectures

ABSTRACT To date, low‐dimensional organic mesocrystals assembled from π‐conjugated molecules remain largely unexplored, let alone hierarchical and heterostructured counterparts with high morphological complexity. Herein, we achieve both homogeneous and heterogeneous mesocrystals of organic donor–acceptor (D–A) complexes by tailoring their compositions and growth kinetics via solution co‐assembly in which 2,5,8,11‐tetra‐ tert ‐butylperylene (TBPe) and 1,2‐dicyanotetrafluorobenzene ( o ‐FP) function as an electron donor and an acceptor, respectively. Under equimolar conditions, their D–A complexes self‐assemble into either unbranched microwire/microtube (MW/MT) mesocrystals or branched mesocrystals, depending on the presence or absence of cyclohexane (CyH) as a weak solvent. Further increasing the molar ratio of TBPe to o ‐FP (5:1) and modulating crystallization rates leads to heterostructured mesocrystals comprising TBPe microparticles (MPs) and TBPe‐ o ‐FP MWs, and matchstick‐, dumbbell‐, and beads‐like heterostructures were realized via site‐selective growth. These TBPe‐based D–A mesocrystals display pronounced two‐photon luminescence behaviors. The co‐assembly strategy is further extended to create additional TBPe‐based D–A mesocrystals, demonstrating its versatility. Mechanistic analysis reveals that controlled growth kinetics and well‐defined epitaxial relationships are essential factors for achieving both homogeneous and heterogeneous mesocrystals. The present work sheds light on the precision synthesis of organic mesocrystals with sophisticated architectures.