Methylated chromenoquinoline dyes: synthesis, optical properties, and application for mitochondrial labeling

Methylated chromenoquinoline dyes were designed and synthesized, and their photophysical properties were investigated. These new fluorescent dyes exhibited relatively high quantum yields, long wavelength emissions, large Stokes shifts, large absorption extinction coefficients and good water-solubility. Importantly, these methylated cation dyes showed a specific staining ability for mitochondria in living cells with low cytotoxicity.