Regioselective bromination of 2-nitro-5,10,15,20-tetraphenylporphyrin,
cyclopropa[b]chlorins, or trans-bis(dicyanomethyl)chlorins occurs in
the pyrrole subunit opposite the substituted ring; exhaustive brominat
ion of functionalized tetraphenylchlorins provides a route to dodecasu
bstitued dihydroporphyrins for the first time.