OH stretching vibrations of phenol-(H2O)(n) clusters (n = 1, 3) in the S-1 state have been observed by UV-IR double resonance spectroscopy, where the fluorescence dip induced by the IR excitation was monitored. The spectra were analyzed by comparing with those of the S-0 state reported in a previous work. It was found that a frequency reduction of the phenolic OH stretching vibration and an enhancement of the interactions among the hydrogen bond network in the cluster were much larger in the S-1 state than in the S-0 state, representing the increase in acidity of phenol upon the electronic excitation. The nonradiative process of the vibrationally excited phenol is also discussed based on the fluorescence-dip spectrum of the deuterated phenol in S-1.