VU0463271 is a potent and selective potassium-chloride cotransporter 2 (KCC2) inhibitor th at displays greatly enhanced potency than its structural analogs VU0255011 (ML077) & VU0240511 (IC50 = 61, 537, and 568 nM, respectively). VU0463271 exhibits much reduced efficacy against the related Na-K-2Cl cotransporter 1 (NKCC1 inhibition max ~37% at 100 μM) and little affinity toward a panel of 68 GPCRs, ion channels, and transporters. Although VU0463271 is reported to exhibit affinity toward mitochondrial translocator protein TSPO (IC50 of 204 nM against PK11195 binding; r at heart) and inhibitory potency against α1B adrenergic receptor (IC50 of 364.7 nM; human α1B CHO transfectants), these proteins are not known to affect chloride homeostasis.