LipoFluor-ER2™ is a cell-permeant stain for the endoplasmic reticulum with unique spectral properties, which makes it particularly useful for antibody double- and triple-labelling experiments. LipoFluor-ER2™ is highly compatible with green, red and far-red fluorophore-labelled antibodies and has been successfully used to image the endoplasmic reticulum in human and other mammalian cell lines.