Mn(II), Co(II), Ni(II), Pd(II) and Pt(II) complexes containing a tetradentate macrocyclic nitrogen ligand i.e. 1,5,8,12-tetraaza-2,4,9,11-tetramethyl cyclotetraaza-1,4,8,11-tetraene, (L), have been synthesized. The ligand was characterized on the basis of elemental analyses, IR, 1H NMR and EI mass spectral studies while that of the complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, mass, IR, electronic and ESR spectral studies. On the basis of IR, electronic, and ESR spectral studies, an octahedral geometry has been assigned for the Mn(II), Co(II) and Ni(II) complexes, whereas square planar geometry were found for the Pd(II) and Pt(II) complexes. In vitro the ligand and its complexes were against two pathogenic fungi (i.e., Alternaria alternata and Aspergillus niger) to assess their growth inhibiting potential.