Reaction of the Huisgen zwitterions, derived from triphenylphosphine and azodicarboxylates with activated alkenes has been studied. The reaction of various ethenetricarboxylates and diethyl azodicarboxylate with PPh₃ gave pyrazolines efficiently. This pyrazoline synthesis is also applicable to 2-substituted acrylates such as trimethyl 2-phosphonoacrylate and methyl 2-(trifluoromethyl)acrylate. The possible reaction mechanism was discussed in comparison with the reaction of acetylenedicarboxylate and Huisgen zwitterions. The selective transformation of pyrazoline products have also been performed.