Used primarily as an intermediate in organic synthesis, especially in the pharmaceutical and agrochemical industries. It serves as a reagent for introducing methylthiomethyl (MTM) protecting groups for alcohols and phenols due to its ability to react selectively under mild conditions. The MTM group can be easily removed later in the synthesis, making it valuable in multi-step reactions. Also employed in the preparation of sulfonium salts, which are useful in methylation reactions and as precursors to ylides in Wittig-type transformations. Due to its reactivity and toxicity, handling requires strict safety controls, limiting its use to controlled laboratory and industrial settings.