The synfacial heterodinuclear μ‐Cot complexes (Cot = cyclooctatetraene) [(CpCr) (CpM)]μ‐Cot (Cp = cyclopentadienyl; M  Fe, 3; M  Co, 4) are formed in a thermal reaction of the mononuclear mixed sandwich compound CpCr(n6‐Cot) and CpMLn [M  Fe, Ln = benzene (Bz); M  Co, Ln = (C2H4)2]. 3 possesses two unpaired electrons whereas 4 has only one unpaired electron and is ESR active. From the molecular structure of 3 and from the ESR data of 4 it can be deduced that the unpaired electrons are localized at the Cr centers predominantly forcing a close electronical relation between the heterodinuclear compounds 3 and 4 and the mononuclear sandwich complexes chromocene and CpCrBz, respectively.