This communication describes the reactions of PhICl2 and N -chlorosuccinimide with Pd-II(phpy)(2) (phpy = 2-phenylpyridine) to afford the novel Pd-IV oxidative addition products Pd-IV(phpy)(2)(Cl)(2) and Pd-IV(phpy)(2)(Cl)(succinimide), respectively. These Pd-IV species are remarkably stable at room temperature. However, upon thermolysis at 80 degrees C, they undergo competing C-Cl, C-C, and C-N bond-forming reductive elimination reactions. Both the accessibility and the observed reactivity of these complexes provide support for a Pd-II/IV mechanism in Pd-catalyzed halogenation reactions.