Well-resolved spectra of styrene-methanol binary clusters SMn, with n = 1-9, have been obtained by the (one-color) resonant two-photon ionization technique using the 0(0)(0) resonance of styrene. The spectra reveal a rapid increase in complexity with the number of methanol molecules in the cluster, associated with van der Waals modes and isomeric forms. Two distinct isomers are identified for each of the clusters studied with the exception of SM4 and SM8. The progressive addition of methanol molecules to the SM complex leads to the formation of stable cyclic and branched cyclic methanol subclusters within the SM, clusters. The spectral shift of the cluster origin reflects the nature of the intermolecular interactions within the binary cluster. Blue shifts are observed for the SM, SM2, and SM3 Clusters and are consistent with hydrogen bonding interactions between the OH groups and the styrene pi-system. A remarkable switch in the spectral shift from blue to red is observed at the SM4 cluster and is consistent with the ring structure of the methanol tetramer. Evidence is provided for intracluster dissociative proton-transfer reactions within the S2Mn+(n > 2) clusters that generate protonated methanol clusters. These reactions may explain the strong inhibition effects exerted by small concentrations of methanol on the cationic polymerization of styrene.