In summary, we have developed a one-step procedure to achieve single atom, isotopic transmutation from 14 N → N in various heteroaromatics. This transformation proceeds through the intermediacy of the corresponding N-triflylated heterocycle, followed by a N aspartate diester-mediated ANRORC process and subsequent succinyl elimination to give the isotopically enriched product. High chemical yields and moderate to high isotopic ratios are typically observed, even for complex or drug-like molecules. Two classification models were implemented to assess isotopic labeling efficiency using a stereoelectronic parameter; both indicated that longer N-C6 bond distances in the neutral or triflylated substrates were associated with enhanced labeling efficiency. Notably, products possessing isotopic enrichment matching that of the labeled dimethyl aspartate can be isolated through a slightly modified procedure, which is valuable for applications requiring high isotopic purity. As nitrogen-containing heterocycles are prevalent in complex functional molecules, such as pharmaceuticals, we envision that isotopic enrichment of these molecules without resorting to lengthy de novo syntheses will enable studies in mechanism elucidation, in vivo metabolomics, spin hyperpolarization, and more.