The results (Table in Supporting Information) showed that decay curves fit best with a double exponential model. The first decay was minimally affected compared to the unsubstituted dyes (0.99-1.72 vs 1.52 s for 4CzIPN and its derivatives), while the second was shorter (8.60-8.81 vs 11.6 s for 4CzIPN and its derivatives). The conjugate lifetimes were consistent across different solvents and peptide conjugations. Notably, in water, 3yb showed increased lifetimes, suggesting small aggregate formation. In DMSO, the quantum yield of unmodified 4CzIPN is 19.7% under excitation at 330 nm (Table , S4 in Supporting Information), aligning with the 10% yield previously reported in aerated toluene. The quantum yield of 3ya in DMSO remained close, while other peptide conjugates showed yields around 7-8%. Under 380 nm excitation, quantum yields were slightly lower. Notably, these compounds still exhibited good quantum yields in water, providing potential for biological applications. To further compare the redox potentials and excited-state energy of the peptide conjugates with unmodified 4CzIPN and a well-known Ir complex [Ir{dF(CF3)ppy}2(dtbpy)]PF6, Cyclic voltammetry (CV) experiments were conducted (Figure , Table in Supporting Information), and excited state potentials were estimated using the Rehm-Weller equation. In the excited states, both conjugates exhibit similar or even stronger oxidative and reductive capabilities when compared to 4CzIPN and the Ir catalysts. They also possess high excited states energy (>60 kcal/mol), with 3za notably reaching 67.6 kcal/mol. ).