phosphoramidate, phosphoranylidenetriazene, and azaphosphole derivatives can be respectively formed when the substituted azidocoumarin 1 reacted with trialkylphosphites (TAP), dialkylphosphonates (DAP), and tris(dialkylamino)phosphines. The known triazinedione was revealed to be a side product in the reactions of carbaldehyde 1 with TAP and tris(dialkylamino)-phosphines. In the same context, when the starting coumarin 16 was allowed to react with P (III) reagents, chromen phosphoramidates and chromen phosphoric triamide derivatives were obtained via Staudinger reaction. Contrary to that pathway, phosphoranylidenetriazen chromen derivative could be isolated and identified when coumarin 16 was allowed to react with tris(diethylamino)-phosphine. The antioxidant activities of 6-newly products were evaluated. The results showed that two from the six screened compounds exhibited good antioxidant activities.