Reversible color switching of bright phosphorescence in purely organic materials for advanced data encryption

whereas the blue crystals revert to green upon heating, demonstrating a reversible phosphorescence-to-phosphorescence switching mechanism. Through a combination of experimental analyses and quantum chemical calculations, we elucidate the underlying mechanism governing this triplet emission color transformation: syn-anti conformational reorientation of bromine-carbonyl substituents: upon solvent inclusion, hydrogen bonding stabilizes the syn-rotamer to yield bright-blue phosphorescence, whereas gentle heating reverts the system to the anti-rotamer for green emission. Exploiting this property, we develop an advanced data encryption platform featuring a dual-layer security system-phosphorescence emission combined with thermal- or solvent-induced stimuli-response-significantly enhancing security in secure data encryption and anti-counterfeiting.