Depending on the stoichiometry and solvent conditions aluminacycles III or IV are formed from the reaction of 1,2,3,4-tetraphenyl-l,4-dilithiumhutadiene (I) with AlCl 3 (II) (see Scheme 1). It has been shown that while IV undergoes intramolecular ionic complex formation to give IVa, III gives IIIa only to a smaller extent. III as well as IV take up two (COD)Ni 0 units forming polynuclear complexes. The proposed structures are discussed. Both III and IV react with NiBr 2 to give octaphenylcyclooctatetraene. In the presence of 1,2-bis(diphenylphosphino)ethane (DPPE) the complex DPPE-tetraphenylcyclobutadienenickel(0) can be isolated.