A series of thieno [2, 3-d]-and thieno [3, 2-d] pyrimidines have been easily synthesized using as key step a deproto-cadmiation–trapping sequence. Some of the compounds thus synthesized were screened for anticancer (cytotoxic) activities, and (S)-2-(6-iodo-2- phenylthieno [2, 3-d] pyrimidin-4-ylamino)-3-phenylpropanoic acid proved to have a significant activity towards liver, human breast and cervix carcinoma cell lines.