As the external pressure exceeds 1.0 GPa, the intensity gradually decreases accompanied by a redshift (Figure ), this is attributed to the reduction in intermolecular distance and molecular planar twisting induced by pressure, where promoted effective intermolecular π-π stacking interactions and strong excitationunexcited molecule coupling leads to resonance dimer emission in the form of a redshifted band. Similarly, in the crystalline state of DBTS, the C-H...O=S interactions are strengthened under high pressure, leading to the restriction of vibrations, thereby rigidifying the molecular framework. The unique luminescent mechanism of PIEE molecules provides new insights for the development of new luminescent materials and novel optical sensors.