Dibenzothiophene and derivatives-substituted imidazolium salts as NHC precursors have been designed as novel C^C*NHC bidentate main ligands to construct two novel heteroleptic iridium(III) complexes containing two NHC-based main ligands with dibenzothiophene motif in this work. The emission peaks of these two novel NHC-based iridium(III) luminophores are centered at ca. 530 nm and the quantum efficiency of IrNHC-S is up to 79.8%. Beside excellent photophysical properties, CV results revealed that these two novel NHC-based iridium(III) complexes comprising dibenzothiophene motif exhibited very low oxidation potential (<0.5 V vs Fc/Fc+). At last, ECL performance under various conditions are comprehensively investigated in this work. Though ECL efficiencies under current experimental conditions are still lower than the benchmark of Ru(bpy)32+ due to lack of suitable co-reactants, the novel kinds of NHC-based iridium(III) complexes revealed in this study would indeed provide some new avenues to design ECL luminophores with low oxidation potential and emission colors different from Ru(bpy)32+ in the future.