New pyrimidinethione derivatives were synthesized in good yields from 2,6-bisarylmethylene-N-propylpiperidone as starting material. These derivatives were allowed to react with chloroacetic acid and 2-bromopropanoic acid to give thiazolopyrimidine derivatives. Bisarylmethylene was also reacted with 2-amino thiouracil to yield pyridothiopyrimidine derivative, which reacted with halo acids to give pyridothiazolopyrimidine derivatives. The structures were elucidated on the basis of NMR, MS, FTIR and elemental analyses. Further, the cytotoxic activity of the synthesized compounds were evaluated in vitro against human HepG-2 (liver carcinoma), PC-3 (prostate adenocarcinoma) and HCT116 (colorectal carcinoma) cell lines using MTT assay.