Eight iridium complexes by employing 3-methyl-6-(naphthalen-2-yl)-imidazo [2,1-b] thiazole (mn2mt) and 3-methyl-6-(naphthalene-1-yl)imidazo [2,1-b] thiazole (mn1mt) as the primary ligands, as well as picolinic acid (pic), isoquinoline-3-carboxylic acid (3-IQA), quinoline-2-carboxylic acid (2-QA), and 2-(pyridin-2-yl)phenol (hppy) as the auxiliary ligands, were synthesized for applications where organic optical function materials are required. On top of that, their structures, photoluminescence, and elec-trochemical properties were thoroughly investigated. More specifically, their maximum emission wave-lengths can be detected in the range of 557-609 nm, while the luminous colors span from the green to the standard red region. Interestingly, by employing the synthesized IrIII complexes as emitters, light -emitting diode (LED) chips based on InGaN chip excitation were fabricated, which divulged good perfor-mances.(c) 2022 Elsevier B.V. All rights reserved.