PhI(OAc)2 has previously been reported as a reagent for the direct arylation of C–H bonds in benzoxazole in a PdII/IV-mediated process. However, evidence reported here suggests this reagent degrades to iodobenzene under the literature reported reaction conditions. Further, we present evidence for the rapid formation of Pd0 nanoparticles in this reaction, leading us to question what is the active catalytic Pd phase in coupling chemistry?Iodobenzene is rapidly generated from phenyl iodonium diactate in DMSO at 150 °C, which serves as the substrate in catalytic C–H bond functionalisation of benzoxazole mediated by palladium.