It is used as the intermediate of the drug pyrimethamine and in the synthesis of medicine and dye. p-Cyanobenzyl chloride is p-chlorobenzene acetonitrile, which is an intermediate for the preparation of 3-methyl-2-(4-chlorophenyl) butyric acid, which can be used to prepare pyrethroids such as fenvalerate and deltamethrin to kill insects agent, Chemicalbook and can be used in the pharmaceutical industry to prepare pyrimethamine. Intermediate of the drug pyrimethamine. For the manufacture of p-chlorobenzyl alcohol, p-chlorobenzaldehyde, p-chlorobenzene acetonitrile, etc. It is an intermediate for the synthesis of ER-330 fluorescent whitening agent, and can also be used in pesticides, medicines, etc.