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Click Chemistry Building Blocks
Our portfolio includes azide-, alkyne-, DBCO-, BCN-, TCO-, and tetrazine-functionalized building blocks, such as fluorescent dyes that span the full visible spectrum and reactive intermediates, designed for both copper-catalyzed (CuAAC) and strain-promoted (SPAAC) click reactions.
Our Click Chemistry Technologies

iFluor® Azides/Alkynes — Superior brightness and photostability for demanding imaging applications
FastClick™ — Reagents containing click-assisting groups (CAGs) for accelerated CuAAC reactions
DBCO/BCN — Copper-free click chemistry for live cell and in vivo labeling
Click Chemistry Pairing Guide

Use this guide to identify compatible reactive group pairings for your click chemistry labeling experiments. Each row shows a reactive group on your biomolecule and its compatible dye/reagent partner from the AAT Bioquest catalog.
Your Biomolecule Has
Use Dye/Reagent With
Reaction Type
Catalyst Required
Azide (-N₃)
Terminal Alkyne
CuAAC
Cu(I) + ligand
Azide (-N₃)
DBCO
SPAAC
None (copper-free)
Azide (-N₃)
BCN
SPAAC
None (copper-free)
Terminal Alkyne (≡CH)
Azide
CuAAC
Cu(I) + ligand
DBCO
Azide
SPAAC
None (copper-free)
BCN
Azide
SPAAC
None (copper-free)
TCO (trans-cyclooctene)
Tetrazine
IEDDA
None
Tetrazine
TCO / norbornene
IEDDA
None
Alkyne Building Blocks

Alkyne-functionalized dyes react with azide-modified biomolecules via copper-catalyzed azide-alkyne cycloaddition (CuAAC).
  • iFluor® alkynes spanning UV to near-infrared wavelengths
  • XFD alkynes as Alexa Fluor® alternatives
  • Tide Fluor™ alkynes optimized for FRET applications
  • Terminal alkynes for standard CuAAC click reactions
  • Applications in EdU cell proliferation and metabolic labeling
DBCO Building Blocks

DBCO-functionalized dyes enable copper-free strain-promoted click reactions with azide-labeled targets.
  • Dibenzocyclooctyne chemistry for live cell labeling
  • No copper catalyst required—biocompatible for in vivo use
  • iFluor® and XFD DBCO dyes across visible spectrum
  • Fast reaction kinetics without cytotoxic metals
  • Ideal for glycan labeling and cell surface modification
  • Higher reactivity, bulkier, more hydrophobic
BCN Building Blocks

BCN-functionalized reagents provide an alternative strain-promoted chemistry for copper-free click reactions.
  • Bicyclononyne reactivity with azides
  • Smaller size than DBCO for reduced steric hindrance
  • Suitable for protein and nucleic acid labeling
  • Compatible with live cell applications
TCO Building Blocks

TCO-functionalized dyes participate in ultrafast inverse electron-demand Diels-Alder reactions with tetrazines.
  • Trans-cyclooctene chemistry for fastest bioorthogonal reactions
  • Reaction rates 1000× faster than standard click chemistry
  • Ideal for real-time imaging of rapid biological processes
  • Pretargeted imaging applications in vivo
Tetrazine Building Blocks

Tetrazine-functionalized dyes react with TCO, cyclopropene, and other strained dienophiles.
  • Complementary partner for TCO-based click chemistry
  • Fluorogenic tetrazines for turn-on detection
  • Multiple color options across visible spectrum
  • Applications in pretargeted radioligand therapy
Azide Building Blocks

Azide-functionalized dyes react with terminal alkynes in CuAAC reactions and with strained cyclooctynes (DBCO, BCN) in copper-free SPAAC reactions.
  • iFluor® azides for superior brightness and photostability
  • XFD azides as cost-effective Alexa Fluor® alternatives
  • Tide Fluor™ azides for FRET probe synthesis
  • Compatible with EdU, AHA, and other metabolic labels
  • Full spectral range from blue to near-infrared

This document (01.0319.251203r1) was last updated on Sat Feb 28 2026. All trademarks and registered trademarks mentioned herein are the property of their respective owners.