The synthesis of [1,2,3]triazolo[4,5-b][1,5]-, imidazolo[4,5-b][1,5]-, and pyrido[2,3-b][1,5]benzodiazepines is described. The antidopaminergic and anticholinergic activities of the compounds have been examined by the respective in vitro [3H]spiperone and [3H]QNB receptor binding assay. The neuroleptic potential has been further evaluated in terms of their ability to produce hypothermia and catalepsy in mice and a conditioned avoidance response in rats. Only compounds from the triazolobenzodiazepine series show antipsychotic potential. The lack of activity in the imidazolo- and pyridobenzodiazepine series indicates that the basicity of the heteroarene moiety may be determinant for activity.