1,1′-Thiocarbonyldiimidazole is a chemical compound used in organic synthesis as a coupling agent for peptide synthesis, specifically in amide bond formation. It facilitates the coupling of amino acids or peptides by activating carboxylic acids, leading to the formation of peptide bonds. This reagent is known for its efficiency and reliability in peptide chemistry, making it a popular choice in the pharmaceutical and biotechnology industries for the synthesis of peptides and peptide-based drugs.