SIMA (dichloro-diphenyl-fluorescein) is a dye with spectral properties similar to HEX but with a higher quantum yield.
SIMA azide is used to produce fluorescently labeled primers and hybridization probes for quantitative PCR. Oligonucleotides with a SIMA label can be easily generated via azide-alkyne cycloaddition between SIMA azide and alkyne-containing oligonucleotide.