Coordination chemistry of transition metal complexes incorporating Schiff base ligands semi-, thiosemi and S-methylisothiosemicarbazones pyrodoxals (PLSC, PLTSC and PLITSC, respectively) has not been exploited to any great extent. Except for the pioneer work of an Italian researcher, this monograph contains, for the first time, extensive summary of the synthesis and characterization of the complexes incorporating this class of ligands. In fact, the PLSC and PLITSC-based complexes are reported for the first time. This monograph describes the syntheses, physical/chemical properties, structural analyses and antibacterial activities of Cu, Fe, Ni and V complexes with the new Schiff base ligands i.e. PLSC and PLITSC, as well as with the previously known PLTSC ligand. The monograph targets not only synthetic and coordination chemists but crystallographers as well. It is worth noting that this work is particularly of interest to researchers who seek for inadequately exploited areas of coordination chemistry as these recently synthesized ligand systems form biologically active complexes and, thus, possess a high scientific potential for the researchers who crave for challenges.