Because indole was produced early by mixing indigo and fuming sulfuric acid,So early research on indole was carried out for its application in the dye industry. In addition to traditional dyes such as indigo, indigo and indoline, indoles are also used in the synthesis of some new dyes, such as cationic yellow GLL, red indophenolphthalein, etc. Indocyanine Green G, as a dye medicine, can help diagnose and diagnose various liver diseases and cardiovascular and cerebrovascular diseases through angiography.
