A series of isatin derivatives, 1-butyl-5/7-chloro/fluoro-3-((4-methoxybenzyl)imino)indolin-2-ones (3a-d), 6-butyl-chloro/fluoro-6H-indolo[2,3-b]quinoxalines (4a-h), and 5/7-chloro/fluoro-3-((4-methoxybenzyl)imino)indolin-2-ones (5a-h) were synthesized and characterized by using Fourier transform (FT)-IR, (1)H- and (13)C-NMR spectroscopy, mass spectrometric and elemental analysis. The substances were further subjected to in vitro cytotoxicity evaluation against HeLa, SK-BR-3, and MCF-7 cells. The results showed that quinoxalines 4d, 4e, and 4g; and indolin-2-one 5f display significant in vitro cytotoxic activities against HeLa cells and further the compound 4d has resulted in highest cytotoxicity in the entire series studied. In addition, 5f was shown to display substantial activity against all the three cell lines used in the current study.