IR spectra of the OH stretching vibrations of 2-naphthol-B (B = H2O and CH3OH) clusters in S-1 have been measured by photofragment detected IR spectroscopy (PFDIRS). In this spectroscopy, a tunable IR light pulse excites the OH stretching vibration of the electronically excited 2-naphthol-B, which is prepared by a W Light pulse. The vibrationally excited cluster immediately predissociates to generate a 2-naphthol fragment in S1. By monitoring the emission only from the 0(0)(0) band of the fragment with a monochromator while scanning the IR frequency, a background free IR spectrum of the OH stretching vibration of the cluster in S-1 has been successfully obtained. By comparing the IR spectra of the cluster in S-1 with those of in S-0, the effect of the electronic excitation on the frequency change of the OH stretching vibration in the cluster is discussed.