In an attempt to establish novel candidate with promising anticancer activity, two derivatives of (benzo[d]thiazol‐2‐yl)thiophene backbone 1 and 14 were synthesized, and they further reacted with various chemical reagents to afford the corresponding substituted thiophene derivatives 6, 8, 10, 15, 17, and 20, thieno[3,2‐d]pyrimidine derivatives 2–5, 7, 9, 16, 21, 23, and 24, thieno[3,2‐b]pyridine derivatives 11–13, and thieno[3,2‐e][1,4]oxazepine derivative 18. Structures of prepared compounds were affirmed via spectral and elemental data. Among the obtained compounds, seven derivatives 2, 3, 4, 5, 11, 12, and 13 were chosen by National Cancer Institute, USA. Such compounds were screened for their antitumor activity versus 60 cancer cell lines in one‐dose (10 μmol) screening assay. The outcomes showed that all selected compounds exhibited moderate to high anticancer activity towards many cancer cell lines among which compounds 5 and 11 exerted potent antitumor activity against numerous malignant growth cell lines particularly Ovarian Cancer IGROV1.