Quinazolinediones have gained special interest among researchers as they are known to have many pharmacological and medicinal uses. Here, we report an efficient way to synthesize quinazolinediones through the cyclization of acyclic ureido-benzoate esters, catalyzed by anhydrous zinc chloride under mild conditions. A series of quinazolinediones was synthesized in good yield by reacting the corresponding ureido-benzoate esters using this protocol. The quinazolinedione products were characterized using NMR, IR, HRMS spectroscopy and single crystal x-ray diffraction analysis. We also present here a most plausible mechanism for the cyclization reaction. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim