L-3-Nitrophenylalanine is primarily used in biochemical research as a non-natural amino acid. It serves as a key component in the study of enzyme mechanisms, particularly in understanding substrate specificity and enzyme kinetics. This compound is often incorporated into peptides and proteins to investigate their structure-function relationships. Additionally, it is utilized in the development of fluorescent probes and markers due to its nitro group, which can participate in various photochemical reactions. In medicinal chemistry, L-3-Nitrophenylalanine is employed in the design and synthesis of novel drug candidates, especially those targeting enzymes or receptors where the nitro group can enhance binding affinity or modulate activity. Its unique properties also make it valuable in the field of bioorthogonal chemistry, where it is used to introduce specific functionalities into biomolecules for further chemical modifications.