Introduction. The incorporation of traceable isotopes into organic molecules has diverse applications across chemistry, biology, and materials science. Specifically, isotopic labeling is instrumental in studying organic reaction mechanisms and evaluating biologically relevant molecules. Nitrogen-15 labeling, in particular, induces dipolar NMR activity in nitrogencontaining compounds, thus enabling the utilization of various powerful analytical techniques (Figure ). Nitrogen heterocycles are prevalent in drug compounds, agrochemicals, materials, and natural products, making their selective modification crucial for discovery campaigns in these industries. Given the ubiquity of nitrogen heterocycles in functional molecules, especially pharmaceuticals, and the significance of isotopic labeling in applications like biomolecular NMR, 1,3-5 structural analysis, in vivo metabolomics, mechanism elucidation, solution-state mechanics, and spin hyperpolarization (particularly by SABRE-SHEATH, Figure ), we anticipated that a direct method for isotopically labeling nitrogen heteroaromatics would be highly valuable. Even modest levels of isotopic labeling (8-10% N) can considerably enhance signal-to-noise ratios in N NMR, enabling such commonly used techniques in the analysis of isotopically impure compounds. Nonetheless, applications of N-labeled compounds are limited by the availability of enriched reagents to prepare labeled compounds through chemical means, with N-labeled amino acids being the most common reagents. Existing methods for isotopic labeling of heteroaromatic nitrogen(s) are generally inefficient, often necessitating the de novo synthesis of the desired enriched isotopologues. Therefore, an approach to directly label the skeletons of such compounds would be of great value.