(Trimethylsilyl)methyl azide has been found to be a convenient source for generating the methanimine anion (CH2=N-) in a flowing afterglow device. The acidity (388 ± 5 kcal/mol) and electron affinity (0.5 ± 0.1 eV) were established and compared to those of a theoretical prediction. Ion-molecule reactions of the anion were explored and it was found to transfer a hydride to oxygen, nitrous oxide, carbon dioxide, carbonyl sulfide, and carbon disulfide and to undergo sulfur atom transfer with the last two reagents. Methanimine anion also reacts with ethylene oxide to produce the novel 2-azallyl anion (CH2=NCH2-) which was briefly investigated with respect to its acidity (388 ± 5 kcal/mol), electron affinity (0.8 ± 0.3 eV), and reactivity. In the process of carrying out this study it was found that azide ion, which is typically considered to be inert, reacts with carbon disulfide with a rate constant of 3.8 X 10-11 cm3 molecule-1 s-1 to generate the thiocyanate anion.