A series of highly luminescent cyclometalated rhodium (III) complexes, with photoluminescence quantum yields up to 0.65 in thin films, have been designed and prepared. The strong luminescence property is realized by the judicious choice of a strong σ-donor cyclometalating ligand with lower-lying intraligand state and the ability to raise the d-d excited state. This is the first report to demonstrate the capability of rhodium(III) complexes as high efficient light-emitting materials for organic light-emitting devices. Compelling external quantum efficiencies of up to 12.2%and operational half-lifetime of over 3, 000 hours have been achieved.