Used as a bioluminescent substrate in bioassays and molecular imaging, particularly in luciferase-based reporter systems. Enables detection of gene expression, protein-protein interactions, and cellular activity in live cells and small animal models. Its high sensitivity allows for real-time monitoring with low background signal. Commonly applied in research involving calcium signaling, reactive oxygen species, and apoptosis due to its ability to participate in light-emitting reactions with photoproteins like aequorin.