It has been shown that various pyrido-, quinolino-, pyrazino-and qunoxalinotetrazoles can efficienly be used as azide components in the Cu-catalyzed click reaction with alkynes. This method allows for efficient synthesis of a wide variety of N-heterocyclic derivatives of 1,2,3-triazoles.1,2,3-Triazoles are biologically important units. 1 Pyridotriazoles and quinolinotriazoles are particularly interesting as they exhibit a wide range of biological properties, including control of arthropod pests, 2a substance-related disorders, 2b ATP-competetive inhibition of vascular endothelial growth factor receptors I and II, 2c antibacterial, 2d and antimicrobacterial activity. Unarguably, the Cu-catalyzed click chemistry 3 of azide with alkyne is the most efficient way to assemble the 1,2,3-triazole ring 4 (eq. 1). However, preparation of pyrido-and quinolinotriazoles is not straightforward since these azides exist in equlibrium between closed form (tetrazole A) and open form (azide B) (eq. 2). 5(1) Usually, the position of this equilibrium depends on several factors, such as nature of substituents, 5 solvent 6 and temperature. 5 Thus, it has been reported 7a that NO 2 group at the C-6 position of tetrazole favors the open form (azide B). On the contrary, tetrazoles with NO 2 , COOH, and Cl groups at the C-8 position, and unsubstituted tetrazole predominantly exist 7,8 in closed form A. It should be mentioned that pyridotetrazole has been employed in the preparation of organometallic complexes of late transition metals. 7a Furthermore, there have been contradictory reports 9,10 on the employment of tetrazoles in the click reaction. For instance, it has been shown that pyridotetrazoles, existing in closed form, are inert toward click reaction under standard conditions. 9 By other hand, there have been two reports10a,b in which single examples of successful click reaction of generated in situ pyridotetrazoles with alkynes were demonstrated. Moreover, when this manuscript was under preparation, a paper describing successful click reaction of purinotetrazole, which mainly exists in open form, has appeared. 10c Accordingly, motivated by the high biological importance of pyridyl-and quinolinylcontaining triazoles 2 and intrigued by the contradictory results on employment of triazoles in click reaction, 9,10 we undertook investigation aming at the development of efficient method for employment of differently substituted tetrazoles in synthesis of heterocyclic derivatives of 1,2,3-triazoles. Herein, we wish to report that various pyrido-quinolino-, pyrazino-and qunoxalinotetrazoles 1 can efficiently be employed in click reaction with alkynes to give the corresponding heterocyclic derivatives of 1,2,3-triazoles 2 (eq. 3).