Potassium salts of phenylpiperazine (Phpzdtc), fluorophenylpiperazine (F-Phpzdtc) and nitrophenylpiperazine (N-Phpzdtc) dithiocarbamates and their manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by elemental analyses, IR, UV-VIS, magnetic moment measurements and thermal analysis techniques. On the basis of experimental data, the dithiocarbamates (dtcs) have been observed to coordinate to the metal ions via both sulphur atoms of the -NCS2 group forming metal complexes with a metal to ligand ratio of 1:2. The thermal reactivity and antimicrobial activity of the ligands and their metal complexes were also studied. The decomposition of the metal complexes resulted in the formation of the corresponding metal thiocyanates or cyanates as stable intermediates. Phpzdtc was found to be microbiologically more active than its nitro and fluoro derivatives and biological activity of the dtc ligands either remained unaltered or decreased on complexation with metal ions.