An efficient approach is reported for the direct and sustainable construction of quinazolin-4(3H)-ones through a three-component reaction of isatoicanhydride, primaryamines, and bromoacetyl bromide or chloroacetyl chloride in the presence of K2CO3 in DMSO. With bromoacetyl bromide, mono- or dibrominated quinazolinone scaffolds were obtainable in a chemo- and regioselective manner.