CL 218872 is a potent and selective positive allosteric modulator (agonist) at the benzodiazepine site of GABA_A receptors, with preference for those containing the α1 subunit. It is primarily used in neuroscience and pharmacological research to study the specific roles of α1-containing GABA_A receptors in mediating effects such as sedation, anxiolysis, hypnosis, and muscle relaxation. Its high selectivity allows researchers to differentiate the contributions of α1 subtypes from other GABA_A receptor populations in behavioral and neurophysiological studies, including investigations into anxiety disorders, sleep regulation, and epilepsy.