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The rapid synthesis of diverse substituted polycyclic quinazolinones was achieved by two orthogonal Ugi four-component reaction (Ugi-4CR)-based protocols: the first two-step approach via an ammonia-Ugi-4CR followed by palladium-catalyzed annulation; in the second approach, cyanamide was used unprecedently as an amine component in Ugi-4CR followed by an AIBN/tributyltin hydride-induced radical reaction. Like no other method, MCR and cyclization could efficiently construct many biologically interesting compounds with tailored properties in very few steps.