APJ receptor agonist 1, a biphenyl acid derivative, is a potent APJ receptor (APJ-R) agonist ( EC 50 s 0.093 and 0.12 nM for human and rat APJ-R, respectively). APJ receptor agonist 1 displays in vitro potency to apelin-13, the endogenous peptidic ligand for the APJ receptor. APJ receptor agonist 1 has the potential for the research of heart failure.