ML-077, also known as VU0255011, is a highly selective, potent, saline soluble, "best in class" KCC2 antagonist for high fidelity in vitro studies on KCC2 function with IC(50)=537 nM. ML-077 is cell permeable and exhibits submicromolar potency, and shows greater than 10-fold selectivity over other closely related NKCC transporters.