Department of Chemistry, National Institute of Technology, Patna-800 005, Bihar, India E-mail : madhub252@gmail.com Department of Chemistry, Science College, Patna-800 005, Bihar, India Manuscript received 23 August 2012, revised 12 February 2013, accepted 13 February 2013 The stable complexes of CoII, NiII, CuII, ZnII and CdII with (O, N, S) donor triazole derivatives, viz. 4- salicyldimino-3-methyl-5-mercapto-1,2,4-triazole (H2 salmtr) and 4-salicyldimino-3-phenyl-5-mercapto-1,2,4-triazole (H2 salptr) of composition [M(HL)2 ] (M = CoII, NiII, CuII, ZnII or CdII and H2L = H2 salmtr and H2 salptr) as well as [MLB] (M = NiII, CuII, ZnII or CdII and B = H2O or Py) have been prepared, analysed and their probable structure have been suggested from the studies of magnetic susceptibility, electrical conductance, IR data and electronic absorption spectral measurements. The bischelate [M(HL)2 ] (M = CoII, Nill or CuII and H2L = H2 salmtr and H2 salptr) shows UV spectral and magnetic moment values consistent with distorted octahedral geometry. The Znll and CdII bischelates and monoligated complexes [MLB] (M = ZnII, CdII and H2L = H2 salmtr or H2 salptr) are four coordinated tetrahedral while [NiLB] and [CuLB] (B = H2O or Py and H2L = H2 salmtr or H2 salptr) are planar. The CuII, ZnII and CdII complexes and ligands were screened for some antibacterial activity. The antimicrobial properties followed the order : H2 salmtr < H2 salptr < ZnII < CdII < CuII (bischelates). The antifungal activity of [CdLPy] and [CuLPy] was greater than ZnLPy.