In the interests of developing our research on compounds with a pyrazinone nucleus, cyclohomologues, characterised by the presence of one diazepinone nucleus, were prepared. The 5-[(dialkylamino)alkyl]-3,5-dihydro-2-methyl/phenyl-4H-pyrido[2,3- b][1,4]diazepin-4-ones obtained by means of condensation of the 2-(dialkylamino)alkylamino-3-aminopyridines with ethyl acetyl- or benzoyl- acetate, were subjected to pharmacological experimentation in order to evaluate their effect upon mice with regard to exploratory activity, motor coordination, and spontaneous activity. In addition their analgesic activity was evaluated and also their anti-strychnine, anti-cardiazole, anti-amphetamine and anti-reserpine activities.