SiR-BCN is a bicyclo[6.1.0]nonyne (BCN) derivative of the fluorophore silicon rhodamine (SiR). SiR-BCN contains a short PEG linker between the SiR fluorophore and the BCN moiety. SiR-BCN reacts quickly with tetrazine and azide derivatives to form covalent linkages. Small molecules, peptides, oligonucleotides or proteins bearing the appropriate tetrazine or azide can be conjugated to SiR-BCN. SiR excitation and emission are compatible with GFP and/or m-cherry fluorescent proteins. It can be imaged with a standard Cy5 filterset.
