Vibrational spectroscopy of jet-cooled benzonitrile and its clusters, benzonitrile-(H₂O)_1-3, and benzonitrile-(CH₃OH)_1-3, has been carried out by using stimulated Raman-UV (ultraviolet) and IR-UV (infrared-ultraviolet) double resonance methods. CC stretching (ν₁₂), CN stretching (ν_CN), CH stretching (ν_CH), and OH stretching (ν_OH) vibrations have been examined for each species, and characteristic frequency shifts were observed for ν_CN and ν_OH upon the cluster formation. The cluster structures were detemined by comparing the observed spectra with those obtained by ab initio calculations with HF/SCF (Hartree-Fock self-consistent field) 6-31G(d,p) basis set. It was found that the stable structures of benzonitrile-(H₂O)_n and benzonitrile-(CH₃OH)_n are of the ring form, in which a linear chain of (H₂O)_n cluster of (CH₃OH)_n cluster is hydrogen bonded to the CN group and to the ortho hydrogen of benzonitrile. A size dependent transmutation of the hydrogen-bond structure between H₂O or CH₃OH and the CN group of benzonitrile was clearly identified for those clusters. In the small size cluster, the OH group of H₂O or CH₃OH is hydrogen-bonded perpendicularly to the CN triple bond (π-type hydrogen bond), while in the larger size clusters the OH group forms hydrogen bond linearly to the nitrogen atom of the CN group (σ-type hydrogen bond). The lifetimes and the relaxation of the vibrationally excited benzonitrile and its clusters were also investigated by the Raman pump and UV probe technique. The lifetimes of ν₁₂ and ν_CN vibrations of bare benzonitrile were longer than 1 μs. For benzonitrile-H₂O and benzonitrile-(CH₃OH)_n, on the other hand, the lifetime of the ν₁₂ level is less than 1 ns. The relaxation channels for benzonitrile-(CH₃OH)_n have been characterized by observing the electronix transition from the relaxed levels or the transition of the dissociation product. It was concluded that the main relaxation channel after the ν₁₂ excitation is the intracluster vibrational redistribution (IVR), while the ν_CN excitation is followed by the vibrational predissociation (VP).