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Herein, an efficient and regioselective Rh(III)‐catalyzed [4+2] annulation/lactonization cascade of indoles with 4‐hydroxy‐2‐alkynoates at room temperature to access the furo[3′,4′:4,5]pyrimido[1,6‐a]indole‐1,5(3H,4H)‐diones is described. This method features mild reaction conditions, operational simplicity, excellent regioselectivity, broad substrate scope with good functional group tolerance, and good to excellent yields.