Aim. Analysis of the scientific literature over the past decade has shown that large synthetic possibilities towards creating new and effective drug substances have heterocyclic compounds, in particular the derivatives of 1,2,4-triazole. 1,2,4-Triazole is a structural fragment of many synthetic drugs. The special interest cause ylidene hydrazides of 2-(5-R-1,2,4-triazole-3-ylthio)acetic acids as potential biologically active compounds, among which highly effective medicines can be found. With the aim of finding new biologically active compounds the derivatives of 2-((4-R-5-(thiophene-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)aceticohydrazides have been synthesized, their physical-chemical properties have been studied with the use of modern methods, namely elemental analysis, IR,1H-NMR spectroscopy, and their individuality by HPLC-MS. Materials and methods. N'-R1-еden-2-((4-R-5-(thiophene-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)aceticohydrazides were received by adding aromatic (2-BrC6H4, 2,3-(OCH3)2C6H3, 3,5-(OCH3)2C6H3, 4-N(CH3)2C6H4, 3,4-F2C6H3, 2-NO2C6H4,4-NO2C6H4, 4-OHC6H4, 2-OHC6H4, 4-FC6H4, 2-CI-6-FC6H3) or heterocyclic (2-SC4H3, 5-NO2-2-C4H2O) aldehyde to an equivalent amount of the appropriate 2-((4-R-5-(thiophene-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)aceticohydrazide in the acetic acid medium. The study of physical-chemical properties of obtained compounds was carried out according to the methods outlined in SPU. Chromato-mass-spectral studies were performed on hazarding chromatograph Agilent 1260 Infinity HPLC equipped with mass spectrometer Agilent 6120 with ionization in electro-spray (ESI). Conclusion. This suggests the possibility for further study of biological action of the synthesized compounds. As a result of studies the N'-R1-eden-2-((4-R-5-(thiophene-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)aceticohydrazides have been synthesized and their physical-chemical properties have been studied.