Abstract:The novel 2-((1R,2S)-2-((E)-4-substitutedstyryl) cyclooctyl)benzo [d]thiazoles (12-14) were synthesized from the reaction of 10-(4-substitutedbenzylidene)bicyclo[6.2.0]decan-9-ones (5a-8a) with 2-aminothiophenol (11) in the presence of p-TsOH at reflux conditions in good yields. The antiproliferative activities of 12-14 were determined againts C6 (rat brain carcinoma) and HeLa (human cervical carcinoma) cell lines using BrdU cell proliferation ELISA assay. 5-Fu (5-fluorouracil) was used as standard. The antiproliferative activities of 12-14 and the control were investigated on eight concentrations (5, 10, 20, 30, 40, 50, 75 and 100 µM). The results showed that the synthesized compounds had significant antiproliferative activity and low cytotoxicity effects.