Thionyl chloride is widely used in organic synthesis as a chlorinating agent. It is particularly effective in converting alcohols and carboxylic acids into their corresponding alkyl chlorides and acyl chlorides, respectively. This transformation is crucial in the production of pharmaceuticals, agrochemicals, and other fine chemicals. Additionally, it is employed in the synthesis of dyes, pigments, and polymers, where precise chlorination is required.

In the battery industry, thionyl chloride serves as an electrolyte solvent in lithium-thionyl chloride batteries. These batteries are known for their high energy density and long shelf life, making them suitable for applications in medical devices, military equipment, and remote monitoring systems.

Thionyl chloride is also utilized in the production of pesticides and herbicides, where it acts as an intermediate in the synthesis of active ingredients. Its ability to introduce chlorine atoms into organic molecules enhances the efficacy of these agricultural chemicals.

Furthermore, it is used in the preparation of inorganic chlorides and as a dehydrating agent in various chemical reactions. Its versatility and reactivity make it a valuable reagent in both industrial and laboratory settings.