The mildoxidation of sydnone-benzoylhydrazonehybrids with leadoxide in acetic acid/dichloromethane solution inducted their intramolecular cyclization to provide the corresponding 2,5-disubstituted-1,3,4-oxidiazole derivatives. The sydnone moiety has been efficient preserved for the future work in the mildoxidation. J. Heterocyclic Chem., (2009).