Abstract: Disclosed are conjugates comprising a dendrimer and a ligand, which is a functionalized congener of an agonist or antagonist of a receptor of the G-protein coupled receptor (GPCR) superfamily, for example, wherein the functionalized congener is an A1 adenosine receptor agonist having a purine nucleoside moiety and a functional group at the N6 position of the purine nucleoside moiety, wherein the functional group has the formula (I): N6H—Ar1—CH2—C(?O)NH—R1 (I), wherein Ar1 and R1 as defined herein. Also disclosed are pharmaceutical compositions, methods of treating various diseases, and a diagnostic method employing such conjugates.