Reaction of 2,4-dichloroquinoline-3-carbonitrile (1) with 4-methylpiperidine gave 2-chloro-4-(4-methylpiperidin-1-yl)quinoline-3-carbonitrile (2). Acid hydrolysis of 2 afforded the corresponding 2-quinolinones 3, which were N-alkylated in DMF to form the 1-methyl, -ethyl and -phenacyl quinolinones 6a–c. Fusion of 6a–c with hydrazine hydrate gave the 3-aminopyrazolo[4,3-c]quinolin-4-ones 8a–c. Diazotisation of 8a,b followed by reaction with sodium azide afforded the novel 3-azidopyrazolo[4,3-c]quinolin-4-ones 9a,b.