We report on the design and synthesis of triscyclometalated iridium (Ir) complexes that contain aryloxy groups at the end of diamino linkers, which exhibit an extraordinarily long-emission lifetime, and were prepared by regioselective substitution reactions offac-tris-homoleptic cyclometalated Ir complexes, fac-Ir(tpy)(3) (tpy = 2-(4'-tolyl)pyridine). It was found that the Ir(tpy)(3) complex, equipped with approximately one to six 6-N,N-dimethylamino-2-naphthoic acid (DMANA) groups through the appropriate alkyl linkers, exhibited remarkably long-emission lifetimes of up to 216 mu s in DMSO/H2O at room temperature through a reversible electronic energy transfer effect between the Ir complex core and the organic chromophore moieties; however, under the same conditions, the lifetime offac-Ir(tpy)(3) was 1.4 mu s. Regarding the mechanistic aspects, the relationship between the emission lifetimes of the Ir complexes and the structures and numbers of the conjugated chromophores, linker lengths, solvents, positions of the chromophores on the Ir(tpy)(3) core, and related items are discussed.