Used primarily as a key intermediate in the synthesis of thyroid hormones and related analogs, especially in the preparation of labeled or modified forms of thyroxine (T4) and triiodothyronine (T3). Its structure incorporates iodinated aromatic rings that mimic the natural hormone core, making it valuable in biochemical research for studying thyroid receptor binding, hormone transport, and metabolism. The Fmoc-protected amino group allows for solid-phase peptide synthesis, enabling incorporation into larger peptide conjugates for use in immunoassays, diagnostic probes, or drug delivery systems targeting thyroid-related pathways. Commonly employed in the development of thyroid hormone analogs with altered activity or tissue selectivity for therapeutic or imaging purposes.