Pyrocatechol its sulfonic acid is often present in the urine of many mammals. Small amounts of catechol occur naturally in fruits and vegetables along with the enzyme polyphenol oxidase. Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut) the colorless catechol oxidizes to reddish-brown benzoquinone derivatives.

Mitazalimab (ADC-1013; JNJ-64457107) is an FcγR-dependent CD40 agonist that targets tumors by activating antigen-presenting cells like dendritic cells (DC), initiating tumor-reactive T cells, promoting tumor-specific T cell infiltration and destruction of tumors, and remodeling the tumor-infiltrating myeloid microenvironment .

3,3'-Diethylthiadicarbocyanine iodide i a potential sensitive probe.