Tetramethylammonium perchlorate is used as an intermediate in organic and chemical synthesis. It is used as mobile phase in HPLC analysis and quantification of olanzapine, clozapine and N-desmethylclozapine. It acts as a supporting electrolyte in the electrochemical reduction of 1-bromodecane, 1-iodododecane, 2-iodooctane, and 2-bromooctane on a mercury cathode.