Abstract2‐Phenyl‐1, 2, 3‐triazole‐4‐formylhydrazine (2) was prepared by hydrazinolysis of the corresponding ester 1. Reaction of 2 with CS2/KOH gave the oxadiazole derivatives (3) whichviaMannich reaction with different dialkyl amines furnished3‐N, N‐dialkyl derivatives (4a–c). Also, condensation of 2 with appropriate aromatic acid in POCI3yielded oxadiazole derivatives (5a–c), or with aldehydes and ketones afforded hydrazones (6a–c). Cyclization of (6a–c) with acetic anhydride gave the desired dihydroxadiazole derivatives (7a–c). On the other hand, reaction of dithiocarbazate (8) with hydrazine hydrate gave the corresponding triazole derivative (9) which on treatment with carboxylic acids in refluxing POCI3yielded s‐triazole [3, 4–b]‐1, 3, 4‐thiadiazole derivatives (10a–b). The structures of all the above compounds were confirmed by means of IR,