The present work is aimed to synthesize a new series of quinazolin-4(3H)-one derivatives with substituted dithiocarbamate side chain. The proposed derivatives were synthesized by reacting 3-aminoquinazolin-4(3H)-one with carbon disulphide and alkyl/aralkyl halides. All the structures of the final compounds were ascertained based on spectral studies (IR, 1H-NMR, and Mass). The compounds were evaluated for in vitro cytotoxicity against MCF 7 human breast cancer cell lines at concentrations of 1μg/ml, 10 μg/ml and 50 μg/ml. The antibacterial activity was assayed against four different strains, Escherichia coli, Klebsiella pneumonia Gram-negative bacteria and Bacillus subtilis, Staphylococcus aureus Gram-positive bacteria. Among all the compounds tested, the compound 5l (X, X'=Br; R = -CH2C6H5NO2 (m)) showed 45% inhibition at 50 μg/ml in cytotoxic assay. The same compound 5l exhibited highest antibacterial activity with MIC of 16.4 μg/ml and 12.6 μg/ml against E. coli and K. pneumonia respectively. The compound 5k (X, X' = Br; R = CH2C6H5) next in the order showed MIC of 27.6 μg/ml of 16.7 μg/ml against B. subtilis and S. aureus respectively.