Potent and selective antagonist of the G protein-coupled receptor identified as EBI2 (GPR183) (IC50 values are 11 and 15 nM for human and mouse EBI2 receptors, respectively). This compound exhibits selectivity for EBI2 over other receptors, enzymes and transporters. In addition, NIBR189 blocks oxysterol-induced migration of U937 monocyte cells.