13C-Carbon is the most available source of carbon-13. It is a relatively inexpensive solid material, which can be easily converted to calcium carbide-13C2. In current work, Ca13C2 was used for in situ generation of 13C2-acetylene in 1,3-dipolar cycloaddition and [4+2] cycloaddition reaction. For the first time, 1H-1,2,3-triazoles-4,5-13C2 and isoxazoles-4,5-13C2 were synthesized using calcium carbide-13C2. A Diels-Alder type cycloaddition of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine and Ca13C2 was investigated, and the best way for the synthesis of 3,6-di(pyridin-2-yl)pyridazine-4,5-13C2 was proposed for the first time. Here we perform a detailled description of NMR spectra of 13C2-labeled triazoles, isoxazoles and 3,6-di(pyridin-2-yl)pyridazine.