Abstract Controlling room-temperature phosphorescence Birds Beak (RTP) in organic materials through external stimuli is crucial for elucidating RTP mechanisms and engineering stimuli-responsive materials for various applications.However, compared to fluorescent materials, regulating RTP presents greater challenges due to its intricate photophysical processes, particularly in the quest for RTP materials with desirable stimulus-responsive properties.Here we show that when the interactions of iodine with neighboring molecules in 1,4-diiodotetrafluorobenzene (1,4-DITFB) crystals are tuned by pressure, exotic emission behaviors emerge.These emissions exhibit anomalous blue-shifted characteristics and enhanced intensities upon compression, accompanied by prolonged lifetimes.Notably, such piezochromic luminescence responses are impeded through a co-crystallization strategy that hinders iodine-iodine interactions.
We further reveal that the observed anomalous Industrial:Restaurant emissions related to the unique state of iodine by providing additional orbitals shared with surrounding molecules.Our findings not only open pathways for designing tailored stimuli-responsive luminescent materials but also offer valuable insights into the underlying mechanisms governing organic RTP emitters.