Self‐Assembled Bent Perylenediimides.

The properties of π‐functional materials are predominantly influenced by both their molecular structures and interactions between π‐systems. Recent advancements have focused on modifying the geometry or topology of π‐molecules from planar to nonplanar conformations to tailor molecular properties. However, the interactions among nonplanar π‐molecules remain largely unexplored, likely due to the significant reduction in contact surfaces arising from their curved structures. Herein, we investigated the electro‐optical properties and π‐stacking behaviors of a series of bent perylenediimides (B‐PDIs) with gradual changes in bending angles, achieved by altering the lengths of linear alkyl chains connecting the two nitrogen positions of each PDI. Curvature‐dependent self‐assembly of these bent PDIs is observed, which is primarily driven by dipole‐dipole interactions rather than dispersion forces. More importantly, fine‐tuning intermolecular coupling through bending enables excited‐state symmetry‐breaking charge separation in [n]B‐PDIs (n = 16, 12) in the crystalline solid state. [ABSTRACT FROM AUTHOR]