A new group of 2,4,5-triarylimidazoles containing N,N-dimethylaminoethoxy or piperidinyl ethoxy group at the para position of the C-5 phenyl ring were synthesized and their cytotoxic activities were evaluated on three different breast cancer cell lines using MTT assay. The compounds contain various substituents at the para position of C-2 phenyl ring. Among the synthesized compounds, 4-(5-(4-(2-piperidin-1-yl)ethoxy)phenyl)-4-phenyl-1H-imidazol-2-yl)phenol (11e) and 1-2-(4-(2,4-diphenyl-1H-imidazol-5-yl)phenoxy)ethyl) piperidine (11h) with IC50s of less than 0.1 lM on all three cell lines were the most potent cytotoxic compounds.