A new first series from 2-substituted quinoxalines (3-6) were synthesized using o-phenylenediamine with aryl bromomethyl ketones as a key starting material. Moreover, a new second series from 2-oxo-1,2,3,4-tetrahydro-benzo [g] quinoxaline (8-10) were obtained from the reaction of naphthalene-2,3-diamine with ethyl chloroacetate. The structures of the two compound types were confirmed by spectral data studies along with elemental microanalysis. The cytotoxic effects of the synthesized compounds were tested using a MTT colorimetric assay in MCF-7 cells. Four of the compounds, given numbers 4, 5, 9 and 10, were found to induce significant levels of cytotoxicity. Compounds number 5 and 9 showed promising assay results and were tested in the non-cancerous cell line MCF-10A and neither of them showed cellular deterioration. Furthermore, compound 9 was reported to suppress tubulin polymerization. These findings were confirmed by the docking study results demonstrating a remarkable binding affinity of compound 9 to tubulin active site. These findings suggestes that compound 9 has a pharmacological potential as an antineoplastic drug in MCF-7 cells.