Excited-state hydrogen bonding effect on dynamic fluorescence of coumarin 102 chromophore in solution: A time-resolved fluorescence and theoretical study

►Time-resolved fluorescence spectra of coumarin 102 in alcoholic solvents are performed. ►Dual fluorescence has been assigned to free C102 and a hydrogen-bonded complex. ►The equilibrium becomes in favor of hydrogen-bonded forms in excited states.