Zinc complexes with Bis[2-(o-hydroxyphenyl) benzothiazolato ligands (ZnPBS-0) and Bis[2- (o-hydroxynaphthyl) benzothiazolato ligands (ZnPBS-05) were synthesized, and luminescent properties of these materials were investigated. The emission band found that it strongly depends on the molecular structure of introduced ligand and was tuned from 525 nm to 535 nm by changing the ligand structures. Spreading of the ${pi}-conjugation$ in 2-(o-hydroxyphenyl) group gives rise to a blue shift. On the other hand, spreading of the ${pi}-conjugation$ in benzothiazole groups leads to a red shift. The EL properties also showed good consistency with their differences of ligand structure. Bright-blue EL emission with a maximum luminance of 8300 $cd/m^{2}$ at 11V was obtained from the organic light - emitting diodes (OLEDs) using ZnPBS-0 as emitting layer. It was also found that the newly synthesized materials were suitable to be used as emitting materials in organic EL device.