As eries of dye@MOF composites were synthesized through in situ encapsulationo fl uminous rhodamine B( RhB) molecules into ab lue-emissive zirconium-naphthalene-based metal-organic framework (Zr-MOF). The fabricated RhB@Zr-MOFc omposites exhibit tunable dual-emissive characteristics due to the process of resonante nergy transfer from Zr-MOF to RhB. Notably,o ne of the RhB@Zr-MOF composites (R@D3)e xhibited aw eak emissiona t4 20 nm and as tronge mission at 607 nm, for which the two emissions possess large distinctionsi nl ocation and intensity and can be referenced with each other in sensing analytes. By using relative fluorescence intensity insteado ft heir absolute fluorescencei ntensitya st he detection signals, R@D3s erved as ab uilt-in self-calibrated platformt os electively detect Fe 3 + and Cr 2 O 7 2À ions in water.C ompared with the pristine Zr-MOF,t he R@D3 composite showse nhanced sensing selectivity to Fe 3 + and higher sensibility to Cr 2 O 7 2À .T hiss tudy displays the advantageso fc ombining organic dyes with robust Zr-MOFsi nt uning fluorescencea nd sensing performance.