Provided is a method of inhibiting heterodimerization of HIF-2α to HIF1β (ARNT) comprising binding certain small molecules to the HIF-2α PAS-B domain cavity but not to HIF1α and inhibiting HIF-2α heterodimerization to HIF1β (ARNT) but not inhibiting HIF1α heterodimerization to HIF1β (ARNT). Those certain small molecules are also referenced synonymously as HIF2-HDI and HIF2α heterodimerization inhibitors and also simply as certain small molecules.