Organosulfur synthesis comprises bond-forming and functional-group interconversion methods that produce organic compounds containing carbon–sulfur bonds or transform one organosulfur class into another. The concept is bounded by sulfur attached to an organic framework and excludes purely inorganic sulfur chemistry. Its defining reactivity follows sulfur across several oxidation states, including thiols, sulfides, disulfides, sulfoxides, sulfones, sulfonium salts, sulfur ylides, sulfinates, and sulfonates. Nucleophilic substitution by sulfur anions, electrophilic sulfur transfer, radical addition, and metal-catalyzed C–S coupling are principal bond-forming modes. Reactions at sulfur(IV) can change both oxidation state and connectivity through sulfoxide activation, sulfonium formation, ylide chemistry, and sulfinate conversion ^[1]. Sulfur-transfer reagents provide complementary routes in which a defined sulfur unit is delivered to an organic substrate ^[2]. The field is distinguished from organoselenium and organophosphorus synthesis by sulfur's characteristic oxidation-state ladder, nucleophilicity, and leaving-group behavior.