Aim: To design and synthesize bivalent ligands for adenosine A 1–dopamine D 1 receptor heteromers (A 1–D 1 R), and evaluate their pharmacological activities. Methods: Bivalent ligands and their corresponding A 1 R monovalent ligands were designed and synthesized. The affinities of the bivalent ligands for A 1 R and D 1 R in rat brain membrane preparation were examined using radiolabeled binding assays. To demonstrate the formation of A 1– ...