SiR-alkyne is the N-propargylcarboxamide derivative of the fluorophore silicon rhodamine (SiR). Sir-alkyne reacts with azide derivatives in the presence of copper (I) to form 1,2,3-triazoles linkage. Small molecules, peptides, oligonucleotides or proteins bearing the appropriate azide can be conjugated to SiR-alkyne. SiR excitation and emission are compatible with GFP and/or m-cherry fluorescent proteins. It can be imaged with a standard Cy5 filterset.