C–H amination is a powerful strategy for the rapid construction of nitrogen-containing molecules from readily available precursors. In this study, we report a Co(III)-catalyzed C5–selective amination of thiochromones using anthranils as convenient aminating partners. The protocol displays broad substrate scope, excellent regioselectivity, and good functional group tolerance across both thiochromone substrates and anthranil coupling partners. The obtained C5–aminated thiochromones are readily transformed into diverse sulfur-containing heterocyclic frameworks, demonstrating their value as synthetic intermediates. Overall, this work establishes an efficient and site-selective approach for the functionalization and diversification of thiochromone scaffolds.