Thiomandelic acid is primarily utilized in the synthesis of pharmaceuticals, particularly in the development of enzyme inhibitors. It serves as a key intermediate in the production of compounds that target specific enzymes involved in various diseases. Additionally, it is employed in organic chemistry research for the preparation of thioester derivatives, which are valuable in studying biochemical pathways. Its role in medicinal chemistry is significant due to its ability to modulate biological activity, making it a crucial component in drug discovery and development processes.