Geometric Evolution of Perylene‐Based Intermolecular π–π Dimers Toward Static and Dynamic Multicolor Emission

Controllably achieving multicolor emission from single‐molecule‐based organic solids is of great significance, yet it remains a challenge because of the inherent complexity of molecular packing motifs. Herein, multicolor emission is governed by tailoring the geometries of π–π dimers. Using perylene (PE) as a planar π‐fluorophore, we strategically design a compound, 3‐(4‐(1,2,2‐triphenylvinyl)phenyl)perylene (pTPE‐PE), which integrates a tetraphenyl ethylene (TPE) substituent with multiple rotatable phenyl rings to modulate the PE‐based π–π dimer formation. On the one hand, pTPE‐PE crystallization produces four polymorphs exhibiting green, yellow, orange, and red emission color, which are static presentations of the dimer model. This static multicolor emission is directly linked to π–π interactions within the dimers: a smaller interplanar distance and a larger overlap ratio between π–π PE units result in more strengthened interactions and more red‐shifted emission. On the other hand, the observed multicolor transitions under pressure (yellow → orange → red) via dimer compression and thermal stimuli (sky‐blue → green → orange) through dimer (dis)assembly provide dynamic presentation of the dimer model. Consequently, polymorphism/piezochromism/thermochromism not only provides direct experimental evidence for exciton modulation from the perspective of the simplest supramolecular dimer model, but also offers insights for designing intelligent optical materials.