Abstract A series of indolin-2-one analogues were designed and synthesized, and all of them exhibited excellent in vitro potency. The structure and in vivo activity or toxicity relationship (in-vivo SAR) investigation of indolin-2-one structural analogues was carried out. In vivo efficacy studies indicated that 3b significantly suppressed tumor growth in HT-29 and NCI-H460 xenografts without causing significant loss of body weight. Kinase assay ...