Resorufin ethyl ether is primarily used as a fluorescent dye in various biochemical and cellular assays. Its application is significant in the field of molecular biology, where it serves as a substrate for detecting enzymatic activity, particularly in assays involving oxidoreductase enzymes. The compound's fluorescence properties make it an excellent marker for tracking cellular processes and monitoring real-time biological reactions. Additionally, it is utilized in high-throughput screening to identify potential drug candidates by measuring changes in fluorescence intensity. Its stability and sensitivity also make it suitable for use in diagnostic kits and research studies focused on oxidative stress and metabolic pathways.