Multimetallic transition metal complexes can facilitate unique C-C bond cleavage reactions. For example, the first C-C bond cleavage of benzene by any metal was achieved by a trimetallic titanium hydride cluster. A multimetallic approach is of interest as a potentially more accurate mimic of heterogenous catalysts employed industrially, which likely involve cooperative behaviour of multiple metal sites during C-C cleavage. Investigation of a reaction of a series of aluminium complexes with biphenylene has led to some remarkable examples of control over chemoselectivity in C-C bond activation, with bimetallic mechanisms often being invoke to explain the origin of selectivity.