The properties and reactivities of the xanthone (Xn) ketyl radical (XnH center dot) in the doublet excited state (XnH center dot(D-1)) were examined by using two-color two-laser flash photolysis. The absorption and fluorescence of XnH center dot(D-1) were observed for the first time. Several factors governing the deactivation processes of XnH center dot(D-1) such as interaction and reaction with solvent molecules were discussed. The remarkable change of reactivity of XnH center dot(D-1) compared with that in the ground state (XnH center dot(D-0)) was indicated from the experimental results. The rapid halogen abstraction of XnHo(D-1) from some halogen donors such as carbon tetrachloride (CCl4) was found to occur. The halogen abstraction occurred more efficiently in the polar solvents than in the nonpolar solvents. It is suggested that the polar solvents promote the spin distribution of XnH center dot(D-1) of the phenyl ring favorable to the halogen abstraction.