Abstract: The adrenergic receptors or adrenoceptors are a family of G-protein coupled receptors split into ? and ? subclasses. The adrenoceptors have important roles in regulating a myriad of physiological conditions and their malfunction has been implicated in the pathophysiology of a number of diseases. Disclosed herein are a series of novel guanidine and 2-aminoimidazoline compounds which are ligands of the alpha2-adrenoceptor (?2-ARs) subclass of adrenergic receptors. The invention also provides for pharmaceutical compositions comprising the novel compounds. The compounds are suitable for use in the manufacture of medicaments for the treatment of ?2-ARs associated disorders, such as depression, schizophrenia, glaucoma and analgesia.