An Unexpected Boron Rearrangement Leads to a Fluorogenic and Colorimetric BODIPY Probe

Abstract The isolation and characterization of a kinetically stable oxadiazaborinine (ODB) dye are described, which undergoes an unexpected thermal boron rearrangement with a color change and increase in fluorescence. This controllable reaction allows for the use as a practical time‐temperature indicator probe with the advantages of photostability, non‐reversibility, and environmental friendliness.