The formation and quenching of the triplet state of xanthone are studied by femtosecond techniques. As revealed by femtosecond fluorescence spectroscopy, the primarily excited (1)pipi* state decays within 1.5 ps. In a transient absorption experiment, this time constant is associated with a partial rise of a triplet signature. This rise has a second and slower component with a time constant of 12 ps. In the presence of high concentrations of the quencher 1-methylnaphthalene, the slow 12 ps rise component is absent. This finding gives strong evidence that the biphasic rise of the triplet absorption of xanthone is due to a sequential mechanism, namely, a (1)pipi* --> (3)npi* with fast intersystem crossing followed by a (3)npi* --> (3)pipi* internal conversion. Furthermore, an analysis of the concentration dependence of the quenching kinetics allows one to pin down the intrinsic transfer time of the triplet energy from xanthone to 1-methylnaphthalene to similar to1 ps.