Engineering phosphorescence and pH-responsive fluorescence of molecular luminophores and elastomers

Organic ultralong room-temperature phosphorescence (RTP) enables time-gated optical readout by separating long-lived triplet emission from short-lived autofluorescence. However, coupling RTP with biochemical responsiveness at both the molecular and materials levels remains a fundamental challenge due to the lack of a luminophore-intrinsic design principle for linking chemical responsiveness to triplet-state photophysics and the conflict between rigid, shielded microenvironments and deformable polymer matrices. Here we present an ArKMK design paradigm that electronically couples an aromatic ketone to a pH-responsive α-methyleneketone within a carbonyl-rich framework, yielding homophthalic anhydride (HA) and homophthalimides as a family of luminophores that integrate pH responsiveness with RTP. To preserve long-lived emission in elastomeric matrices, we further develop a two-pots-in-one (TPiO) strategy that separately preforms hydrophilic and hydrophobic segments and then co-reacts them to generate phase-separated microenvironments in biodegradable polyesters. The resulting materials reconcile mechanical compliance with triplet-state stabilization, while covalently integrating ArKMK luminophores through the same esterification chemistry. These biodegradable polyesters enable time-gated subcutaneous imaging, gastrointestinal tracking and wound-status reporting through coupled RTP and pH-indicating fluorescence. This work establishes a molecular-to-polymer framework for integrating pH responsiveness with long-lived triplet emission in soft, biodegradable materials. Combining organic room temperature phosphorescence with biochemical responses is desirable, but challenging. Here, the authors report the development of a design combining an aromatic ketone and a methylene ketone to give materials with room temperature phosphorescence and pH-responsive fluorescence.