The gas-phase reactions of octaethylporphyrin (HIP, III) with 12 metal monocations, which were produced by laser ablation of Al, V, Cr, Fe, Ni, Nb, Mo, Hf, W, Re, Pt, and Au targets in an ICR-FTMS instrument, revealed three possible reaction pathways: (i) charge transfer; (ii) metal incorporation (ligation) with loss of H,; and (iii) "dimerization" of the ligation product from pathway ii by addition of another porphyrin without further loss of H, The differences in metal behavior are discussed. The reaction of a mixture of hexaethyldimethylporphyrin (H2P, I) and pentaethyltrimethylporphyrin (H2P, II) with neat Fe+ was also investigated: it was found that more than half of the Fe+ reacts by charge exchange and that the lower-alkylated porphyrin (I), which has the higher ionization energy (IE), reacts more slowly in charge exchange but with the same rate in the both ligation and "dimerization" reactions as the higher alkylated porphyrin (H2P, II).