A novel Schiff base ligand 4-{[3-(4-hydroxy-3-methoxyphenyl)prop-2-enalidene]-amino}-5-ethyl-4H-1, 2, 4-triazole-3thiol [HETT] was derived by condensing 4-amino-5-ethyl-4H-1, 2, 4-triazole-3thiol [AETT] with 3-(4-hydroxy-3-methoxyphenyl)prop-2-enal. Ag(I), Zn(II), Hg(II), Co(II) and Ni(II) complexes of HETT were prepared. The HETT and its metal complexes were characterised by various analytical methods. The HETT molecules are found to link to the metal ions, through thiol sulphur after deprotonation and the nitrogen of the azomethine group. The composition of the complexes are found to be ML where M= Ag, ML₂ where M= Zn, Hg and ML₂(H₂O)₂ where M= Co, Ni. Linear polymeric structure is proposed for Ag(I) complex, tetrahedral structure is proposed for Zn(II) and Hg(II) complexes, and octahedral structure is proposed for Co(II) and Ni(II) complexes.