Three new ligands have been prepared in this work, which were chosen to synthesis a new set of transition metal complexes [Cu (II), Ni (II), Hg (II), Cd (II) and Co (II)]. LI=(2-[5-phenyl-2-methylthio-1,3,4-oxadizole]-5-phenyl-1,3,4-oxadiazole), LII=2-(O-chloro benzylidine) hydrazine benzothiazole and LIII=2-(p-hydroxy benzylidine) hydrazine benzothiazole were prepared by Schiff reaction between 2-mercaptobenzothiazole and 2-chlorobenzaldehyde and p-hydroxy benzaldehyde. The new ligands were characterized by the Infra-red spectroscopy and melting points. The metal complexes, were prepared and isolated in pure solid state, and found to be stable toward light, heat and moisture. These new complexes were characterized via FT.IR , UV-Vis Spectroscopy, magnetic and conductivity measurements. In addition the metal contain were determind by atomic absorption measurement. According to the result of the above measurements, the following formula were suggested by atomic absorption measurement. LI complexes: [Cu (LI)2 Cl2]. H2O which was of Oh geometry Ni (LI)2 (H2O)2] (NO3)2. H2O which was of Oh shape [Hg (LI)2 Cl2]. C2H5OH which was of Oh geometry [Co (LI)2 Cl2]. 2C2H5OH which was of Oh geometry [Cd (LI)2] (NO3)2. H2O which was of Th geometry LII complexes: [Cu (LII)2 Cl2].2 H2O which was of Oh geometry [Ni (LII)2 (NO3)2]. 2H2O which was of Oh shape [Co (LII)2 (EtOH)2] Cl3 which was of Oh geometry [Cd LII (NO3)2. H2O which was of Td geometry LIII complexes: [Cu (LIII)2 (H2O)2] Cl2 which was of Oh geometry [Ni (LIII)2 (H2O)2]. (NO3)2 H2O which was of Oh shape [Co (LIII)2 CL2]. 2H2O which was of Oh geometry [Cd LIII (H2O)2]. (NO3)2. H2O which was of Td geometry Different bonding and structural behavior were revealed through the study of the coordination chemistry of the metal complexes of the new ligands. The nature of bonding between the metal ion and the donor atoms of the ligands were demonstrated through the calculaion of Racah parameter and the other ligand field parameters, which were calculated by using the suitable Tanabe-Sugano diagrams