For the lowest excited tripler (T-1) states of the title alpha-haloanthraquinones, the following results are obtained : (1) The shapes of phosphorescence spectra are similar to those of the usual pi pi*-type phosphorescence spectra; (2) the phosphorescence quantum yields are very small; (3) the tripler lifetimes (0.32-260 mu s) are much shorter than that (2.6-2.7 ms) of planar 2-bromoanthraquinone (the beta-bromo compound) with a T-1 state of typical n pi* character. Since calculation of the optimized geometries of alpha-haloanthraquinones indicates the nonplanarity in the central quinone structure, the distortion of the geometrical molecular structure caused by the steric hindrance between the oxygen and halogen atoms may give rise to the appearance of unusually broad phosphorescence spectra. On the basis of the fact that a log-log plot of the nonradiative triplet decay rate constants against the sum of the squares of atomic spin-orbit coupling constants gives an almost straight Line, we conclude that not only a special nonradiative decay process (owing to the nonplanarity in the central quinone structure) but also the internal heavy-atom effect of the halogen atom affects the tripler lifetimes of alpha-haloanthraquinones.