Herein, we describe two efficient one-step approaches to synthesize cyanoarenes bearing functional peptide sequences (Figure ). The first method (Method A) involves the photomediated decarboxylative substitution of a cyanide group in Cz(I)PN. A broad scope of carbazolyl benzonitriles (CzBN) was obtained, but the reaction resulted in the formation of diastereoisomers at the newly formed benzylic center at C-terminus. To further enhance the incorporation efficiency and prevent the generation of two diastereoisomers, we developed a cysteine-selective SNAr reaction using a fluoroisophthalonitrile precursor resulting in the formation of a triscarbazolyl-isophthalonitrile (3CzIPN) dye (Method B). Both the CzBN and the 3CzIPN conjugates exhibit photophysical properties and redox potentials that are similar to or superior to the non-modified 4CzIPN. These properties make them suitable as photocatalysts in various photo-mediated biomolecule functionalizations, both in vitro and at the cellular level. We demonstrated first successful decarboxylative alkynylation and thiol-ene reactions on peptides. As a first example in a complex biological setting, we then realized a proximity-driven labelling next to integrin v3 via aryl azide excitation enabled by a binding peptide-CzIPN conjugate, which showed an excellent overlap with antibody-based imaging.