Colon cancer is the third leading cause of death worldwide; therefore, there is a need for an effective therapy with lower side effects. A series of 8-alkyl-2,4-bisbenzylidene-3-nortropinones 3 & 14-39 was prepared via Claisen-Schmidt condensation of 8-alkyl-3-nortropinones 11-13 with different aromatic aldehydes. The target compounds were screened for their antiproliferative activity. Most of the prepared compounds showed promising antiproliferative activity against many of 60 National Cancer Institute cell lines at 10μM. Furthermore, 8-ethyl-2,4-bis(3,4-dimethoxybenzylidene)-8-nortropin-3-one 29 and its 3,4,5-trimethoxy analog 30 were the most active compounds against HCT116 cell line with IC50 values 0.01 and 0.46μM, respectively. Using CODESSA-Pro software, a significant 2D-quantitative structure-activity relationship (QSAR) model was obtained. The 8-Alkyl-2,4-bisbenzylidene-8-azabicyclo[3.2.1]octan-3-one represents an interesting core for further structural optimization to obtain more promising hits.