CID-16020046 is a novel, potent and selective GPR55 (LPI receptor) antagonist / inverse agonist which inhibits GPR55 constitutive activity with IC50 of 0.15 uM. GPR55 is a G protein-coupled receptor that is weakly activated by some cannabinoids at nM concentrations. CID16020046 has been shown to block GPR55-mediated endothelial wound healing and reverse LPI-inhibited platelet aggregation. The G protein-coupled receptor 55 (GPR55) is a lysophosphatidylinositol (LPI) receptor that is also responsive to certain cannabinoids. Although GPR55 has been implicated in several (patho)physiologic functions, its role remains enigmatic owing mainly to the lack of selective GPR55 antagonists.