different between pyrrole vs porphin

English

From German Pyrrol, corresponding to Ancient Greek ?????? (purrhós, “reddish, fiery”) +? -ole.

pyrrole (plural pyrroles)

(organic chemistry) Any of a class of aromatic heterocyclic compounds containing a ring of four carbon atoms and a nitrogen atom; especially the simplest one, C₄H₅N. [from 19th c.]
- 1998, Georgina Ferry, Dorothy Hodgkin: A Life:
  The way the red crystals absorbed light suggested that the molecule might contain a porphyrin-like structure, a flat ring made up of four smaller rings called pyrroles […].

porphin (plural porphins)

(organic chemistry) A ring or four pyrrole rings linked by methine groups; it is the structure at the centre of hemoglobin, chlorophyll and other porphyrins