BRG1-IN-1 (Compound 11d) is a potent inhibitor of SMARCA4/BRG1. BRG1-IN-1 shows better efficacy than PFI-3 in sensitizing GBM cells to the antiproliferative and cell death inducing effects of Temozolomide in vitro. BRG1-IN-1 enhances the inhibitor effect of Temozolomide on the growth of subcutaneous GBM tumors.