Hematoporphyrin
Hematoporphyrin is a porphyrin prepared from hemin. It is a derivative of protoporphyrin IX, where the two vinyl groups have been hydrated. It is a deeply colored solid that is usually encountered as a solution. Its chemical structure was determined in 1900.
It is used as a photosensitizer in photodynamic therapy. Acetylation of hematoporphyrin followed by hydrolysis of the product of that reaction affords a mixture called hematoporphyrin derivative, which is also used in photodynamic therapy.
Hematoporphyrin has also been used as an antidepressant and antipsychotic since the 1920s.