The adenosine A2A receptor is an example of the G protein-coupled receptor (GPCR) family, which is important in mediating vasodilation, supporting the synthesis of new blood vessels and protecting tissues from collateral inflammatory damage. It is a well-studied receptor with several known molecules for which affinities have been measured. The standardised ChEMBL v.27 dataset contains 3300 molecules with measured inhibition constants (ki) for the A2A target.