AbstractResults are presented for the gas phase thermalized electron attachment reactions of transition metal dithiocarbamates Metal·[S2CN·Et2]n, with n = 3 for the trivalent metals Cr, Mn, Fe, Co and n = 2 for the divalent metals Fe, Co, Ni, Pd and Cu. Details of negative ion mass spectra are given, and these were obtained by use of the complementary methods of in‐beam direct insertion and desorption chemical ionization of samples into temperature and pressure controlled ion source methane gas plasmas. For the tris‐complexes, only small abundances of [M]− were observed, being consistent with the electron entering a metal‐based orbital to give a reduced [MetalII·L3]*− species—the precursor of the observed [MetalII·L2]− or [L]− product ions. For the bis‐complexes, a much higher proportion of the total ion current was carried by [M]−, with [L]− being the next most abundant species in all cases and the principal product in the reaction sequence \documentclass{article}\pagestyle{empty}\begin{document}${[{\rm Metal}^{{\rm II}} \cdot {\rm L}_{\rm 2}] + {\rm e} \to [{\rm Metal}^{\rm I} \cdot {\rm L}_{\rm 2}]^{*-} \mathop {\rightarrow}\limits^* [{\rm L]}^{\rm - } + [{\rm Metal}^{\rm I} \cdot {\rm L}].}$\end{document}. Rearrangement ions [L·MetalI·X]− with X=SH, SCN, NEt2 were also identified for this series which can be accounted for by rearrangement reactions occurring in ligands not fulfilling a bidentate function towards the relevant metal.