Abstract: | Controlled oxidation of palladium nanoparticles provided high‐valent PdIV oxo‐clusters which efficiently promote directed C−H halogenation reactions. In addition, palladium nanoparticles can undergo changes in oxidation states to provide both high‐valent PdIV and low‐valent Pd0 species within one system, and thus a tandem reaction of C−H halogenation and cross‐coupling (C−N, C−C, and C−S bond formation) was successfully established. |