A site-specific oxidative C–H chalcogenation of quinoxalin-2(1H)-ones with various diaryl diselenides/disulfides is presented by employing Selectfluor reagent as an oxidant. The reaction proceeds selectively at the C6 position of quinoxalin-2(1H)-ones, and enables access to a wide array of chalcogenyl quinoxalin-2(1H)-ones. The merits of the transformation involve excellent substrate and functional compatibility, operational simplicity, and the use of a mild oxidant. The present work offers a fundamental basis for the selective synthesis of functional quinoxalin-2(1H)-ones from readily available feedstocks.