Imaging of nitric oxide (NO) in living cells can provide new insights in understanding unsolved pathways in the cardiovascular and neurological dysfunction and many types of cancers. For the detection of NO under physiological conditions, we synthesized a turn-on fluorescent probe comprising CdSe/ZnS quantum dots (QDs) coordinated with dirhodium complex. Emission from CdSe/ZnS-QDs is quenched when coordinated with the dirhodium complex but can be restored upon the displacement by nitric oxide.