Synthesis and assessment of a maleimide functionalized BF2 azadipyrromethene near-infrared fluorochromeElectronic supplementary information (ESI) available: UV-Vis spectra, NMR spectra, conjugation conversion plots, in vivo imaging. See DOI: 10.1039/c5cc06137g

The first water soluble maleimide bearing NIR BF 2 -azadipyrromethene (NIR-AZA) fluorochrome has been synthesised which is capable of rapid thiol conjugations in water with peptides such as glutathione, the cell penetrating peptide (CPP) C(β-A)SKKKKTKV-NH 2 and a thiol substituted cRGD. NIR fluorescence imaging showed rapid cellular delivery of the CPP conjugate and effective in vivo tumour localization for the cRGD conjugate. Aqueous soluble NIR-AZA fluorochrome which undergoes rapid rt bio-conjugations via thiol addition for in vitro and in vivo imaging.