In this study, we have discovered a structurally related series of quinazolines as potent inhibitors of Wnt/β-catenin signaling in colorectal cancer cells harboring mutations in CTNNB1 or APC. We showed that the quinazoline leads suppressed Wnt/β-catenin signaling without altering the level of β-catenin protein in colorectal cancer cells, suggesting that they act on the downstream elements of the pathway. This evidence concerns the gene CTNNB1 and colorectal cancer.