Used as a reagent in organic synthesis, particularly for the methylation of carboxylic acids to produce methyl esters. It is also employed in the preparation of diazo compounds, which are valuable intermediates in various chemical reactions. Additionally, it finds application in the derivatization of analytes for gas chromatography-mass spectrometry (GC-MS) analysis, enhancing detection sensitivity. Its ability to introduce the diazomethane group makes it useful in cyclopropanation reactions, forming three-membered ring structures. It is also utilized in the synthesis of pharmaceuticals and fine chemicals, where precise functional group transformations are required.