${alpha}$,${alpha}$-Dibromovalerophenone and ${alpha}$,${alpha}$-dichlorovalerophenone were prepared and their photochemical behaviors were investigated. The former gives C-Br cleavage products and the latter gives mainly the Yang photocyclization products upon irradiation. The reactivity of the chlorine substituted ketone turned out to be quite different from that of ${alpha}$,${alpha}$-difluorovalerophenone which gives both the cyclization and elimination products from the 1,4-biradical intermediate.