Influence of 2-amino-5-ethylthio-1,3,4-thiadiazole on inhibition of copper corrosion in an aerated 0.50M HCl solution has been investigated using gravimetric and electrochemical techniques Application： 2-Amino-5-ethyl-1,3,4-thiadiazole was used in the synthesis of: 3-(5-ethyl-1,3,4-thiadiazol-2-yldiazenyl)-1-methyl-2-phenyl-1H-indole hetarylazoindole dyes N-(5-ethyl-[1,3,4]-thiadiazole-2-yl) toluenesulfonamide ligand