porphin

noun

por·​phin ˈpȯr-fən 

variants also porphine

-ˌfēn 

: a deep purple crystalline compound C₂₀H₁₄N₄ that is made synthetically from pyrrole and formaldehyde, contains four pyrrole rings joined by =CH− groups so as to give a heterocyclic arrangement, and forms the essential skeletal structure of the porphyrins, heme, and chlorophyll