In this study, benzenesulfonicacid-1-methylhydrazide (bsmh) derivatives such as 2-hydroxy-1-naphtalde-hydebenzenesulfonylhydrazone (Hnafbsmh) and its Ni(II), Pd(II), Pt(II), Cu(II), Co(II) complexes were synthesized. The structures of these complexes were investigated using elemental analyses (FT-IR, LC-MS, UV-VIS), magnetic susceptibility and conductivity measurement techniques. The complexes were found to have general compositions [ML2]. All the synthesized complexes were evaluated in vitro as antimicrobial agents against representative strains of six gram-positive and four gram-negative bacteria and as an antifungal agent by disc diffusion methods. All the bacteria and fungi studied were screened against some commercial antibiotics to compare them with our chemical's zone diameters.