A series of 1,3‐disubstituted‐2‐thioxoimidazolidin‐4‐one and diazine derivatives were synthesized and confirmed through IR, NMR, and mass spectrometry. The in vitro cytotoxic activity of synthesized compounds against HePG2 and MCF‐7 cells were assessed by MTT assay. Furthermore, Aromatase, VEGFR‐2, B‐Raf, cell cycle, Annexin V, caspase‐3 and sulphatase expression by PCR, and β‐catenin expression by western blot were estimated. The results revealed that the synthesized compounds possess cytotoxic activity against HePG2 and MCF‐7 cell lines. Compound 11 (2,2′‐(1E,1′E)‐1,1′‐(hydrazine‐1,2‐diylidene) bis (ethan‐1‐yl‐1‐ylidene) bis (4‐(phenyldiazenyl) phenol) had greater cytotoxic activity than staurosporine (6.24 μg/mL), with IC50 of 2.55 μg/mL against HepG2 cells and (4.21 μg/mL) against MCF‐7 cells. Moreover, the inhibitory activity against aromatase was (0.156 μg/mL), (0.23 μg/mL) against VEGFR2, and (0.25 μg/mL) against B‐Raf. Also, this compound decreased DNA content of HepG2 cells in the S phase and the G2/M phase, and increased the apoptosis in Annexin measurement. By real‐time PCR, This compound up‐regulated the expression of caspase‐3 in HepG2 cells, reduced the expression of sulphatase gene in HepG2 cells, and reduced β‐catenin expression in HepG2 by western blot analysis. Consequently, the synthesized derivatives could be a promising scaffold for the development of potent anti‐cancer agents due to their apoptotic and anti‐inflammatory activities.