Two novel cyclometallated iridium(III) complexes have been prepared with one bidentate or two monodentate imidazole-based ligands, 1 and 2 , respectively. The complexes showed intense emission with long lifetimes of the excited state. Femtosecond transient absorption experiments established the nature of the lowest excited state as 3 IL state. Singlet oxygen generation with good yields (40% for 1 and 82% for 2 ) was establishe...