This study presents a deconstruction–reconstruction strategy for diversifying pyrimidine-containing compounds into various nitrogen heteroaromatics. The approach involves converting pyrimidines into N-arylpyrimidinium salts, which can be cleaved into a three-carbon iminoenamine building block. This intermediate is then used for various heterocycle-forming reactions, enabling the creation of diverse heterocycles such as azoles. The method allows for the formation of heterocycles on complex molecules, which would be challenging to obtain through other methods. The strategy is demonstrated through the transformation of pyrimidines into iminoenamines and subsequent cyclization reactions, showing its applicability to a wide range of pyrimidine substrates. Computational studies support the mechanism of N-arylpyrimidinium salt formation, highlighting the impact of substituents on the reaction barriers. This approach is expected to extend to other heterocycle classes and enhance the diversification of complex molecules in drug and agrochemical development.This study presents a deconstruction–reconstruction strategy for diversifying pyrimidine-containing compounds into various nitrogen heteroaromatics. The approach involves converting pyrimidines into N-arylpyrimidinium salts, which can be cleaved into a three-carbon iminoenamine building block. This intermediate is then used for various heterocycle-forming reactions, enabling the creation of diverse heterocycles such as azoles. The method allows for the formation of heterocycles on complex molecules, which would be challenging to obtain through other methods. The strategy is demonstrated through the transformation of pyrimidines into iminoenamines and subsequent cyclization reactions, showing its applicability to a wide range of pyrimidine substrates. Computational studies support the mechanism of N-arylpyrimidinium salt formation, highlighting the impact of substituents on the reaction barriers. This approach is expected to extend to other heterocycle classes and enhance the diversification of complex molecules in drug and agrochemical development.