This orange fluorescent dye can be used as a nuclear stain with living cells, or as a cell location dye to define cell perimeter in a variety of cell-based assays. Water soluble and membrane permeable, CyTRAK Orange is offered for live cell imaging applications such as nucleus/cytoplasmic and cytoplasm/cytoplasmic membrane translocations, nucleus/cytoplasm translocations, and cell/cell boundary interactions, as well as for cell-based HCS and HTS, fixed-cell, and FISH assays. This versatile fluorescent dye is compatible with existing protocols and is suitable for use across a wide range of imaging platforms. The dye can be used in live cells in combination with common fluors such as GFP fusions, FITC-labeled antibodies, and far-red dyes. It permits the rapid staining of the dsDNA/nuclei of live or fixed cells, fluoresces at 615 nm, and is photochemically and biologically stable. No cell lysing, washing, or RNase are needed for use.