New substituted benzimidazole dithiocarbamate ligand (HL) and a set of its transition metal complexes were synthesized and characterized based on the elemental analyses, IR, MS, solid reflectance, magnetic moment, molar conductance and thermal analyses (TGA and DrTG). From the obtained IR data, HL is a neutral tridentate ligand and its complexes were proposed to have the general formulae [MCl(HL)(H2O)2]Cl2.2H2O (M = Cr(III) and Fe(III)] and [MCl(HL)(H2O)2]ClyH2O (for y = 2: M = Mn(II), Co(II) and Cu(II) and for y = 1: M = Ni(II), Zn(II) and Cd(II)). The molar conductance data revealed that all the metal chelates were electrolytes. From the magnetic and solid reflectance spectra, it was found that the geometrical structure of the synthesized complexes is octahedral. The thermal behaviour of these chelates showed that the hydrated complexes loss water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. Fungicidal activity of the new ligand and its related complexes was evaluated against three soil-borne fungi that cause many destructive diseases as damping off, root and stem rots of many plants. The tested fungi are Fusarium solani, Rhizoctonia solani and Sclerotium rolfesii. Data obtained showed that introducing an electron-withdrawing nitro group in position (5) of benzimidazole ring enhanced the biological potentialities of the parent ligand and some of its transition metal chelates to show better activity than the standard fungicide Pencycuron.