Photophysical kinetic results have played an important role in assessing excited state relaxation pathways in transition metal complexes. The applicability of a kinetic analysis is critically dependent on the quality of the individual decay rates, the temperature range examined, and the model used to extract the activation parameters. The extensive literature describing the temperature dependence of excited state depopulation in d 3 and d 6 complexes permits an evaluation of both the power and limitations of kinetic arguments in assessing the mechanism of excited state relaxation.