3′-Methoxyfurano[4″,5″:3,4]chalcone (compound 2) is a selective A 2A AR antagonist ( IC 50 =33.5 nM) with high affinity. 3′-Methoxyfurano[4″,5″:3,4]chalcone is also a natural product obtained from the bark of Allium cepa L. 3′-Methoxyfurano[4″,5″:3,4]chalcone can promote T cell activation and can be used in cancer immunity research.