A Pd-catalyzed ortho-selective halogenation of benzoxazinone and quinazolinone scaffolds has been described employing N-halosuccinimide as both a halogen source and an oxidant reagent via C–H bond activation. This transformation shows high chemo- and regioselectivities and demonstrates a broad range of benzoxazinone and quinazolinone substrates with different functional groups and has been scaled up to the gram level.