AbstractNumerous clinically used compounds having favorable tranquilizing and toxic properties possess the 1,4‐benzodiazepine skeleton. This group of active substances is readily accessible, e.g. by ring enlargement of quinazoline derivatives, by ring contraction of benzoxadiazocines, and by synthesis from aminobenzophenones, constructing the seven‐membered ring in many cases in one step. The relationships between type and position of substituents and the pharmacological properties are illustrated using 1,3‐dihydro‐5‐phenyl‐1,4‐benzodiazepin‐2