As a second transformation, we investigate C-terminal decarboxylative alkynylation using photoredox catalysis with visible light and the organic dye 4CzIPN (Fig ). We selected dipeptide Cbz-GP-OH (7) as coupling partner, as the decarboxylation is faster on proline compare to other C-terminal amino acids. Decarboxylative alkynylation occurred on Lysmodified peptide-EBXs 3 to give products 8a-c bearing a Gly, a Pro and a Glu C-terminal amino acid respectively (Fig ). As expected, the yield was lower for 8b due to the competition with the C-terminal proline of 3g. In addition, decarboxylative alkynylation was also successful in N-terminal modified EBX reagent 3p to give alkyne 8d in 49% isolated yield.