Substituted triazolinones were prepared by a three-component reaction of aldehydes,hydrazines and azodicarboxylates using TFA as a catalyst. The procedure was convenient and efficient,utilizing readily available substrates. A plausible mechanism for the cascade process is proposed. Substituted triazolinones were prepared by a three-component reaction of aldehydes, hydrazines and azodicarboxylates using TFA as a catalyst. A procedure for convenient and efficient substrates. A plausible mechanism for the cascade process is proposed.