Irradiation of low-lying vibronic levels of Ã2A2 of OClO isolated in solid Ne, Ar, or Kr produces ClOO. Destruction of OClO and production of ClOO in various matrix sites were monitored with IR absorption lines near 1100 and 1440cm-1, respectively. For OClO in solid Ar at 5 K, site selectivity is observed after irradiation at the vibronic line associated with a specific site; decreased intensity of the IR line associated with a specific site of OClO correlates well with increased intensity of the corresponding line of ClOO. Similar behavior is observed for OClO in solid Kr except that formation of ClOO in one site (1412.1cm-1) is invariably dominant. The nature of the carriers of two major sites of ClOO (corresponding to 1416.7 and 1442.5cm-1 in solid Ar, 1412.1 and 1440.7cm-1 in solid Kr) is discussed. Temporal profiles of absorbance AOClO and AClOO were probed after various periods of irradiation until approximately 20%-60% of OClO was destroyed. Excitation of the ν3 vibrational mode of OClO Ã2A2 enhances photodissociation of OClO appreciably. Rates of destruction of OClO in solid Ar or Kr are much smaller than that in solid Ne. The apparent conversion factor, ΔAClOO/(-ΔAOClO) is greater for OClO in solid Ne than that in solid Ar or Kr. Effects of matrix host on photolysis are discussed.