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. |