Unprecedented high fluorescence anisotropy in protic solvents: Hydrogen bond induced solvent caging?

â¿¢Atypical high fluorescence anisotropy is reported for few flavones in protic solvents.â¿¢3HF exhibits high anisotropy in protic solvents when 3MF gives low values.â¿¢Additional hydroxyl groups do not contribute to the anisotropy value of 3HF.â¿¢ESIPT prone flavones form hydrogen bonded cage-like structures with protic solvents.