A simple and efficient one‐pot procedure has been developed for the construction of pyrrolo[1,2‐a]pyrimidines via the three‐component domino reaction of 5‐aminopyrazoles, acetylenedicarboxylates and malononitrile under catalyst‐free, microwave irradiation conditions. The key step in this transformation is the NN bond cleavage reaction of the 5‐aminopyrazole substrate, which has been reported in this context for the first time in this study. The advantages of this protocol include readily available starting materials, short reaction times and good regioselectivity.