Some 1,5-diaryl-3-methyl-1H-pyrazolo[4,5-c]isoquinolines were synthesized and tested for their ability to displace [3H]clonazepam or [3H]Ro 5-4864 from their specificbinding on the central and peripheralbenzodiazepine receptors. None of the tested compounds showed any activity as central binding inhibitors, while most of them were specific as peripheralbinding inhibitors, although they were not very