A new series of diarylamides and diarylureas having 2,3-dihydropyrrolo[3,2-b]quinoline scaffold was synthesized. Their in vitro antiproliferative activities were tested over NCI-60 cancer cell lines of nine different cancer types. Some target compounds showed good inhibition percentages over different cell lines. Among all the target compounds, compound 1f possessing 6,7-dimethoxy-2,3-dihydropyrrolo[3,2-b]quinoline nucleus, amide linker, and 4-chloro-3-(trifluoromethyl)phenyl terminal ring showed high selectivity against MCF7 and MDA-MB-468 breast cancer cell lines more than the other tested cell lines. Its inhibition percentages at $10{mu}M$ concentration over those two cell lines were 84.97% and 87.13%, respectively.