A series of ester formylhydrazones were synthesised by the reaction of alkyl imidate hydrochlorides with formylhydrazine. Treatment of the ester formylhydrazones with acetic acid hydrazide, isonicotinic acid hydrazide, nicotinic acid hydrazide, and 4-hydroxybenzhydrazide resulted in the formation of either 4-acylamino-4H-1,2,4-triazoles or 2,5-disubstituted 1,3,4-oxadiazoles. 3-Alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones were synthesised by the reaction of the ester formylhydrazones with carbohydrazide. Some arylidenamino compounds were synthesised by the reaction of 4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones with several aldehydes. These compounds were characterised by elemental analyses, IR, H-1 NMR, and UV spectral techniques.