Abstract One pot synthesis of alkyl, aryl, heteroaryl mono (2) substituted 4 (3H)- quinazolinones and 2-aryl or heteroaryl, 1-arylmethyl or heteroarylmethyl-1H- benzimidazoles using a water soluble Cu (NO 3) 2. 3H 2 O catalyst at room/ambient temperature in excellent yield. Graphical Abstract One pot synthesis of alkyl, aryl, heteroaryl mono (2) substituted 4 (3H)-quinazolinones and 2-aryl or heteroaryl, 1-arylmethyl or ...