The proteolysis-targeting chimera (PROTAC) is a new technology to degrade a target protein. However, its clinical application is limited currently by lack of chemical binders to target protein. For instance, it is still unknown, whether splicing factor 3B subunit 1 (SF3B1) is targetable by PROTACs. We recently identified a 2-aminothiazole derivative (herein O4I2) to promote the generation of human pluripotent stem cells. In the present work, proteomic analysis on the biotinylated O4I2 revealed that O4I2 targeted SF3B1 and positively regulated RNA splicing.