Corrin is a heterocyclic compound.  Although not known to exist on its own, the molecule is of interest as the parent macrocycle related to the cofactor and chromophore in vitamin B. Its name reflects that it is the "core" of vitamin B (cobalamins). Compounds with a corrin core are known as "corrins".
There are two chiral centres, which in natural compounds like cobalamin have the same stereochemistry.