The gas‐phase reactions of Fen+ clusters, n = 1−6, with COS and CS2 have been investigated by means of Fourier‐transform ion‐cyclotron resonance mass spectrometry. Whereas CS2 predominantly substitutes one Fe atom, COS exclusively affords multiple sulfur transfer and thus opens a synthetic route to gaseous FenSx+ clusters. In the final products such as Fe2S2+, Fe3S2+, and Fe4S4+, the sulfur atoms appear to occupy multiple coordination sites much like in the analogous biogeneous iron‐sulfur clusters. Bracketing experiments find IE(Fe2S2) = 7.2±0.3 eV besides providing upper limits for IE(Fe3S2) and IE(Fe4S4). In accordance with the low IE(Fe2S2), Fe2S2+ does not activate H2 or small hydrocarbons and only exhibits rather limited reactivity towards more reactive substrates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)