Quinazolone Derivatives as medicinal have been explored less extensively however some Quinazolone derivative such as methaqualone (3,o-tolyl,2-methyl 4-oxo Quinazolone) has been studied in much detail as central nervous system depressant as well as anticonvulsant agents. Methaqualone has been found to cause considerable decrease in the seizures induced by pentylenetetrazole or metrazole. Certain Quinazolone derivatives have been demonstrated to possess pronounced antimalarial activity and few have been claimed to be very good febrifuge interest in quinazolone chemistry has increased in recent years. Various organic compounds containing quinazolone nucleus have been found to ppossess varying degree of pharmacological properties.The 2-phenyl,3-ethylphenothiazinyl,4-oxo- quinazolone has been found to exhibit definite antiviral activity against Enceophalomyocarditis virus (EMCV) and Ranikhet disease virus (RDV) in vitro.Certain thiotriazolo quinazolines have been shown to possess antiviral activity against Japanese encephalitis virus (JEV) a RNA virus of high pathogenicity and Herpes simplex virus types (HSV-I) the most common DNA virus, in vitro and in vivo, both. In recent years