Given our group's interest in the synthesis and the structural features of heterobiaryl and bis(heteroaryl) containing peptides, we were keen to develop a new macrocyclization strategy that would allow for facile synthesis of heterobiaryl containing peptide macrocycles without the reliance on transition-metal catalysis or the need to prepare building blocks that are suitably protected for Fmoc SPPS. (N-isocyanoimino)triphenylphosphorane (1), commonly known as Pinc, has proven to be a powerful reagent for macrocyclization. We previously showed that oxadiazole-grafted peptide macrocycles prepared from reagent Pinc possess predictable secondary structure. This is a result of the beta-turn stabilizing effect can be observed in most oxadiazole-grafted macrocycles. Our lab has also previously utilized nitrilium ions intermediates in peptide macrocycles to effect an efficient macrocyclic ring contraction strategy. Given these advances, we were motivated to utilize Pinc and its close relative 2 to generate a series of oxadiazole-and oxazoleheterobiaryl linkages as part of a macrocyclization protocol enabled by the nucleophilic trapping of nitrilium intermediates.