Water- and air-stable complexes comprising the cis-[Re(CO)2]+ core can be synthesized from the (Et4N)[ReBr2(NCCH3)2(CO)2] precursor 1. Complex 1 showed distinctly different chemical and electronic behaviour compared to [ReBr3(CO)3]2-. Substituting the two bromides in 1 with imidazole-like ligands or ,-diimines gave new complexes with potential applications in bioinorganic chemistry and photochemistry. The two acetonitrile ligands are very stably bound and could not be replaced. Under CO pressure, the uncommon complex mer-[ReBr(NCCH3)2(CO)3] 2 was formed from 1. The reaction of 1 with the tetradentate ligand bis(2-pyridylmethyl)glycine (BPG) finally induced a four fold substitution at the metal center to form a [Re(CO)2(L4)]+-type complex.