The preparation of the following mixed ligand complexes has been described: Co(pdtc)2(phos)m [pdtc = phenyldithiocarbazate and phos — triphenylphosphane (tpp), bis- (diphenylphosphino)methane (dpm), bis(diphenylphosphino)ethane (dpe), bis(diphenylphosphino)propane (dpp), or bis(diphenylphosphino)butane (dpb); m = 1 or 2], Co(pdtc)2(amine)n [amine = o-phenanthroline (o-phen), Triethylamine (tea), quinoline (quin), α-picoline (α-pic), or β-picoline (β-pic); m = 2 or 4], and Co(pdtc)2(oxygen donors)x [oxygen donors = n-BuOH or phenylacetamide (paa); x = 1 or 2]. The compounds have been characterised by chemical analysis, molar conductance measurements, electronic and IR spectra. Pseudooctahedral geometries are proposed for all the complexes. The phenyldithiocarbazate anion acts as a bidentate ligand in the SN coordination mode. The biological screening of the prepared complexes has been carried out on some pathogenic bacteria and fungi.