mFluor™ Violet 500 Maleimide is an excellent building block that can be readily used for labeling biomolecules that have a free thiol (SH) group such as antibodies and thiol-modified oligos. mFluor™ Violet 500 dyes have fluorescence excitation and emission maxima of ~405 nm and ~500 nm respectively. These spectral characteristics make them an excellent replacement for Pacific Green™ (ThermoFisher) and BD Horizon™ V500 labeling dyes. mFluor™ Violet 500 Maleimide is reasonably stable and shows good reactivity and selectivity with free thiol group. mFluor™ Violet 500 Maleimide provides a convenient tool to label monoclonal, polyclonal antibodies or other proteins (>10 kDa) for flow cytometric applications with the violet laser excitation. Under the same conditions, mFluor™ Violet 500 dye conjugates are significantly brighter than the corresponding bioconjugates of Pacific Green™ (ThermoFisher) and BD Horizon™ V500 with much stronger absorption, making the mFluor™ Violet 500 conjugates much more sensitive. AAT Bioquest's mFluor™ dyes are developed for multicolor flow cytometry-focused applications. These dyes have large Stokes Shifts, and can be well excited by the laser lines of flow cytometers (e.g., 405 nm, 488 nm and 633 nm).