BMP signaling agonist sb4 is a potent benzoxazole bone morphogenetic protein 4 (BMP4) signaling agonist with a EC50 value of 74 nM, activates BMP signaling by stabilizing intracellular p-SMAD-1/5/9. BMP signaling agonist sb4 activates BMP4 target genes (inhibitors of DNA binding,?Id1?and?Id3) canonical BMP signaling.