Pressure‐Induced Blue‐Shifted Emission in Naphthalene Anhydride Crystals Enabled by Chelating Hydrogen Bonds

Abstract Organic emitters, with their diverse electronic transition behaviors and flexible molecular packing conformations, demonstrate notable photoluminescence (PL) sensitivity to external stimuli, rendering them attractive candidates for piezochromic applications. However, the enhancement of π–π stacking interactions and the formation of excimers under pressure typically lead to redshifted emission in organic emitters, thereby limiting their practical applications. Herein, an anomalous pressure‐induced blue‐shifted emission is reported in naphthalene anhydride (NA) crystals. Systematic theoretical and experimental analyses indicate that NA crystals undergo anisotropic compression under high pressure, which alters the molecular arrangement of NA crystals and facilitates the formation of intermolecular chelating hydrogen bonds. This unique chelating hydrogen bond can lock the spatial position of NA molecules and minimize molecular rotation and energy loss during excited‐state relaxation. Therefore, under high pressure, NA molecules exhibit high‐energy bandgap emissions with small Stokes shifts, resulting in a unique pressure‐induced blue‐shifted PL behavior. This study not only elucidates the modulatory role of hydrogen bonding in the PL properties of NA crystals but also presents a novel strategy to realize anomalous piezochromic behavior in organic emitters.