Fmoc-L-Indoline-2-carboxylic acid is widely used in peptide synthesis as a building block. Its Fmoc (fluorenylmethyloxycarbonyl) protecting group is particularly valuable in solid-phase peptide synthesis, allowing for the stepwise assembly of peptides. The compound is employed to introduce the indoline moiety into peptide chains, which can enhance the biological activity or stability of the resulting peptides. It is also utilized in the development of peptidomimetics and bioactive molecules, where the indoline structure plays a critical role in mimicking natural peptide conformations or interacting with biological targets. Additionally, it finds application in medicinal chemistry research for designing and synthesizing novel drug candidates.