A series of 4-amino-5-cinnamoylthiazoles 3a-p were designed and synthesized as chalcone-like anticancer agents. The synthesized derivatives 3a-p were evaluated for their in vitro antiproliferative activities against three different human cancer cell lines including MCF-7, HepG2 and SW480. Most of compounds could significantly prevent proliferation of tested cell lines. In particular, the pyrrolidine derivative 3e namely (E)-1-(4-amino-2-(pyrrolidin-1-yl)thiazol-5-yl)-3-(2,4-dichlorophenyl)prop-2-en-1-one showed promising activity, especially against HepG2 cells (IC₅₀ = 10.6 μg/ml). Flow cytometric analyses revealed that the prototype compound 3e can prevent the proliferation of HepG2 cells by blockade of the cell cycle at the G2 phase and induction of apoptosis.