The reaction of Cp 2 TiS 5 or Cp 2 TiSe 5 with divalent tin porphyrins of the form (P)Sn leads to the formation of (P)SnS or (P)SnSe, where P is the dianion of tetraphenylporphyrin (TPP), tetra-m-tolylporphyrin (TmTP), tetra-p-tolylporphyrin (TpTP), tetramesitylporphyrin (TMP), or octaethylporphyrin (OEP). These pentacoordinated compounds provide the first examples for the binding of chalcogen axial ligands and an oxo type ligation in main-group metalloporphyrins