Two-photon dissociation of vibrationally excited HOOH and CH3OOH is demonstrated from their 2 nu(OH) stretching overtone state using similar to 205 nm light. Initial vibrational excitation appears to be a prerequisite for accessing the two-photon excited dissociative electronic state in these hydroperoxides, most likely due to the ability of vibrational excitation to improve the Franck-Condon factor. The hydroperoxide excited state accessed through the vibrationally mediated photodissociation process generates OH fragments in their A(2)Sigma(+) electronic excited state. Detection of the OH(A(2)Sigma(+)) fluorescence as a function of the vibrational excitation laser allows recording of the 2 nu(CH) overtone action spectra for CH3OOH with high sensitivity. (C) 2011 Elsevier B. V. All rights reserved.