In this work, a universal synthetic approach to the synthesis of D2-labeled nitrogen heterocycles based on cycloaddition reactions of in situ generated dideuteroacetylene is reported. A key feature of the developed method is the use of dioxane as a deuterium-exchange-proof solvent, which allowed dideuterosubstituted heterocycles to be obtained in up to 99% deuteration. The developed method was demonstrated to be suitable for the synthesis of D2-labeled triazoles, isoxazoles, pyrazoles and pyridazines.