AAT Bioquest


Cyanine is the non-systematic name of a synthetic dye family belonging to the polymethine group. The word cyanin stems from the English word "cyan", which conventionally means a shade of blue-green. Cyanine dyes exhibit large molar absorptivities (~150,000 to 300,000 M-1cm-1) and moderate quantum yields resulting in extremely bright fluorescence signals. Cyanines have proven useful in several fields including photography, biology, laser technology and analytical chemistry. AAT Bioquest offers the largest collection of cyanine dyes that maybe useful as molecular probes for a variety of biological applications. For certain biological applications, cyanines can advantageously replace other conventional dyes such as the fluoresceins and rhodamines.



Cyanine Dyes: Cy3 and Cy5

Among cyanine dyes, Cy3® which fluoresces greenish yellow (~550 nm excitation, ~570 nm emission) and Cy5® which is fluorescent in the red region (~650 nm excitation, ~670 nm emission) are the most popular. Because of their minimal spectral overlap, Cy3® and Cy5® are typically combined for 2 color detection. Cy3® can be detected by various fluorometers, imagers, and microscopes with standard filters for TRITC. Due to its high molar extinction coefficient, Cy3® dye is also easily detected by naked eye on electrophoresis gels, and in solution. Cy5® became a popular replacement for far red fluorescent dyes because of its high extinction coefficient (as small as 1 nmol can be detected in gel electrophoresis by naked eye) and its fluorophore emission maximum in the red region, where many CCD detectors have maximum sensitivity and biological objects give low background interference.

Cyanine Dye Spectra

Absorbance (dotted line) and emission (shaded region) maxima Cy3®(left), Cy5®(middle) and Cy7®(right) dyes.)

Spectral Properties


Table 1. Spectral Properties For Cyanine Dyes: Cy3 and Cy5

Cy Dye
Ex/Em (nm)
Filter Set
Extinction Coefficient (ε)1
Quantum Yield (Φ)2
Cy3532 nm554/568 nmCy3/TRITC150,0000.15
Cy5633-647 nm650/669 nmCy5250,0000.27
Cy7730 nm754/778 nmCy7250,0000.3
  1. ε: is the extinction coefficient (cm-1M-1).
  2. Φ: is the fluorescence quantum yield.


Sulfonated vs Non-Sulfonated Cyanines

Sulfonated and non-sulfonated cyanine dyes exhibit very similar fluorescent characteristics and for many applications they can be used interchangeably. The difference between the dyes is mainly in their solubility. Non-sulfonated cyanines must be dissolved in an organic co-solvent, such as DMF or DMSO, prior to labeling of a biomolecule. While sulfonated cyanines can be used in aqueous conditions (the charged sulfonate groups decrease dye and conjugate aggregation). For purification by dialysis against water or an aqueous buffer, sulfonated cyanines must be used for efficient removal of any unreacted dye. Purification by gel filtration, chromatography, or electrophoresis is adequate for both sulfonated and non-sulfonated cyanines.

Table 2. Spectral comparison of sulfonated and non-sulfonated Cy3, Cy5 and Cy7 dyes.
Ex/Em (nm)554/568650/669754/778
Filter SetCy/TRITCCy5Cy7
Cat No.263191268195161198
  1. ε: is the extinction coefficient (cm-1M-1).
  2. Φ: is the fluorescence quantum yield.


Cyanine Products

We offer a broad selection of cyanine products including reactive dyes and conjugation kits for labeling biomolecules, conjugates, indicators and more.
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Cyanine Reactive Dyes

Select a dye-labeling chemistry for modifying the following reactive groups.

Table 2. Cyanine Reactive Dyes

Click Chemistry


Cyanine-Labeled Secondary Conjugates

Select from a variety of cyanine labeled secondary antibody and streptavidin conjugates for signal amplification detection of primary antibodies.

Table 3. Cyanine-Labeled Secondary Conjugates

Goat Anti-Mouse IgG
Goat Anti-Rabbit IgG


Ordering Information


Table 4. Available Cyanine Dyes

Ex (nm)
Em (nm)
Unit Size
Cat No.
Cy3 aldehyde5555695 mg9010
Cy3 tetrazine5555691 mg910
Cy3 trans-cyclooctene5555691 mg900
DBCO-Cy35555691 mg920
Cy3B acid5605715 mg940
Cy3B alkyne5605711 mg944
Cy3B azide5605711 mg943
Cy3B DBCO5605711 mg945
Cy3B maleimide5605711 mg942
Cy3B PEG8 methyltetrazine5605711 mg947
Cy3B TCO5605711 mg946
Cy3B Tetrazine5605711 mg948
Cy3NS acid555569100 mg190
Cy3NS succinimidyl ester55556925 mg191
Cy5.5NS, acid68370325 mg196
Cy5.5NS succinimidyl ester68370310 mg199
Cy5 aldehyde6516705 mg9011
Cy5 tetrazine6516701 mg902
Cy5 trans-cyclooctene6516701 mg901
DBCO-Cy56516701 mg923
Cy5NS acid651670100 mg194
Cy5NS succinimidyl ester65167025 mg195
Cy7NS acid756779100 mg197
Cyanine 3.5 acid5795915 mg147
Cyanine 3.5 alkyne5795911 mg982
Cyanine 3.5 amine5795911 mg139
Cyanine 3.5 Maleimide5795911 mg149
Cyanine 3.5 monosuccinimidyl ester5795911 mg148
Cyanine 3.5 monosuccinimidyl ester, potassium salt5795911 mg275
Cyanine 3 alkyne5555691 mg144
Cyanine 3 amine5555691 mg145
Cyanine 3 bisacid5555695 mg137
Cyanine 3 bissuccinimidyl ester5555691 mg138
Cyanine 3 bissuccinimidyl ester, potassium salt5555691 mg270
Cyanine 3 hydrazide5555691 mg146
Cyanine 3 maleimide5555691 mg142
Cyanine 3 monosuccinimidyl ester5555691 mg141
Cyanine 3 monosuccinimidyl ester, potassium salt5555691 mg271
Cyanine 5.5 alkyne6837031 mg179
Cyanine 5.5 amine6837031 mg176
Cyanine 5.5 bisacid6837035 mg172
Cyanine 5.5 bissuccinimidyl ester6837035 mg158
Cyanine 5.5 hydrazide6837031 mg177
Cyanine 5.5 maleimide6837031 mg175
Cyanine 5.5 monoacid6837035 mg173
Cyanine 5.5 monosuccinimidyl ester6837031 mg174
Cyanine 5.5 monosuccinimidyl ester, potassium salt6837031 mg283
Cyanine 5 alkyne6516701 mg154
Cyanine 5 amine 6516701 mg155
Cyanine 5 bisacid6516705 mg159
Cyanine 5 bissuccinimidyl ester6516705 mg157
Cyanine 5 bissuccinimidyl ester, potassium salt6516701 mg282
Cyanine 5 hydrazide6516701 mg156
Cyanine 5 maleimide6516701 mg152
Cyanine 5 monoacid6516705 mg150
Cyanine 5 monosuccinimidyl ester, potassium salt6516701 mg280
Cyanine 5 potassium salt6516705 mg255
Cyanine 7 alkyne7567791 mg164
Cyanine 7 amine7567791 mg165
Cyanine 7 bisacid7567795 mg169
Cyanine 7 bissuccinimidyl ester7567795 mg170
Cyanine 7 bissuccinimidyl ester, potassium salt7567791 mg295
Cyanine 7 hydrazide7567791 mg166
Cyanine 7 maleimide7567791 mg162
Cyanine 7 monoacid7567795 mg160
Cyanine 7 monosuccinimidyl ester7567791 mg161
Cyanine 7 monosuccinimidyl ester, potassium salt7567791 mg290
Cy2DIGE NHS ester492508100 nmoles25300
Cy3DIGE NHS ester555569100 nmoles25303
Cy5DIGE NHS ester651670100 nmoles25306
Cy3 biotin conjugate5555695 mg3099
Cy5.5 biotin conjugate6837035 mg3105
Cy7 biotin conjugate7567795 mg3106
Cy7 Styramide *Superior Replacement for Cy7 tyramide*756779100 Slides45066
Cy7 tyramide7567791 mg11064
Cy7.5 tetrazine 1 mg909
Sulfo-Cyanine 5 NHS ester65167010 mg268
Sulfo-Cyanine 5 carboxylic acid65167025 mg266
Sulfo-Cyanine 3 NHS ester55556910 mg263
Sulfo-Cyanine 3 carboxylic acid55556925 mg260