The story of the identification of magnesium isocyanide (MgNC) began with a report by Guélin et al. in 1986 of three doublet lines in the circumstellar envelope IRC +10216. They were unable to match the lines to any known species. In 1993, Kawaguchi et al. published laboratory data for MgNC. Its rotational spectrum matched the unidentified lines. Theoretical work by Ishii et al. helped to confirm the assignment.

MgNC is an unstable radical species. It has a fairly large dipole moment, which contributes toward its observability in the molecular clouds via rotational spectroscopy.