Fluorescent gold nanoclusters with unique luminescence properties have drawn great attention in bioimaging. The gold nanoclusters with controlled multicolor fluorescence may benefit accurate fluorescence imaging. In this work, gold-nanocluster-engineered spiropyran ligands (AuNC-SP) were reported to achieve controlled dual-color imaging under single excitation. Through switching the Förster resonance energy transfer from the gold nanocluster segment to the open-ring state merocyanine by UV-vis irradiation, AuNC-SP possesses reversibly dual-color fluorescence. After AuNC-SP combined with chitosan to form AuNC-SP@CS nanoparticles, the steric protection of chitosan largely improved the oxidative stability of AuNC-SP upon UV irradiation. Moreover, the AuNC-SP@CS could be internalized within cancer cells and released AuNC-SP that further underwent transportation into the nucleus. Thus, the AuNC-SP@CS exhibits excellent and reversible dual-color fluorescence to label not only the cytoplasm but also the nucleus. We envisage the AuNC-SP@CS as an ideal probe for fine subcellular assays in the cell interior.