Nuclear Black™ DCS2 is live cell impermeable. It is the first and novel fluorescence suppression reagent optimized for live-cell imaging applications targeting red fluorescence. Some commonly used nuclear stains for live cell applications may lead to unintended staining of dead or membrane-compromised cells during imaging. Nuclear Black™ DCS2 is formulated to reduce red signals from the nuclei of non-viable or compromised cells, thus enhancing the contrast and clarity of red fluorescent signals from live, healthy cells in microscopy assays. Its cell-impermeable design ensures that it remains outside intact live cells and does not affect the data from live cells. Nuclear Black™ DCS2 is ideal for live-cell fluorescence microscopy, high-content screening, and assays where signal from dead cells interferes with imaging. Its simple protocol integrates easily into existing workflows to improve imaging results.