Convenient and efficient synthesis of novel N- (4-acetyl-4,5-dihydro-5-(7,8,9-substituted-tetrazolo[1,5-a] quinolin-4-yl)-1,3,4-thiadiazol-2-yl)acetamides 4a–j and their in vitro anticancer activity against two cell lines viz., human breast cancer cell line MCF7 and human cervix cancer cell line HeLa were carried out. GI50, LC50, TGI values were evaluated. Two of the compounds 4e and 4i with halogen substituent at 7th position of the target molecules have shown potent activity against human cervix cancer cell line HeLa. DNA cleavage studies revealed that most of these compounds show partial cleavage and few of them show complete cleavage of DNA.