A particular reactivity of 1-cyanomethylpyridinium salts was revealed in the [3 + 2] cycloaddition conditions with alkyl propiolates. Cycloadducts 3 were obtained in reactions carried out at room temperature while refluxing in CH3CN provided unexpected ethyl or methyl 3-(3-cyanoimidazo[1,2-a]pyridin-2-yl)indolizine-1-carboxylates 4. The structure of the new 2:1 azaindolizine-indolizine adducts was secured by X-ray analysis. Methodological efforts have enabled the adjustment of the reactivity towards the formation of 3-cyanoindolizines 3 or cyanoazaindolizine-indolizines 4. A mechanism for the formation of azaindolizine-indolizines was proposed. A portfolio of rare cyanoindolizines and cyanoazaindolizine-indolizines has been successfully obtained.