Color tuning from red to green of bis-cyclometalated iridium(III) emitters based on benzoimidazole ligands in OLEDs: A DFT and TD-DFT investigation

•The spectral nature is correlated with structural variation.•Conjugation length of ligands affects the color tuning and quantum yield.•Luminescent performance is evaluated by combining quantum yield and EL efficiency.•The potential of Ir(III) complexes to be promising OLED materials are explored.