Some 5-[(dialkylamino)alkyl]-8-chloro-3,5-dihydro-2-methyl/phenyl-4H- pyrido[2,3-b] [1,4]-diazepin-4-ones previously prepared, were subjected to pharmacological experimentation in order to verify variation in biological activity induced by introduction of chlorine on the pyridine nucleus and by replacement of pyridinic with a benzenic ring. The effect upon mice with regard to exploratory activity, motor coordination, spontaneous activity, analgesic activity was tested and their anti-stricnine, anti-cardiazole, anti-amphetamine and anti-reserpine activities were also evaluated. The activities of the texted compounds were compared with those already showed by the analogues unchlorinated derivatives (B) and by isosters benzodiazepinones (D).