Thermal treatment of 1,2-bis(3-tert-butylcyclopentadieny1) tetramethyldigermane with [Fe(CO)5] in xylene gave the diiron complex [Fe2(CO)2(μ-CO)2(μ-3-t-BuC5H3Me2GeGeMe2C5H3Bu-t-3)] 1 existing as a mixture of cis and trans isomers (1c and 1t) which were separated by preparative TLC. When the two isomers were heated in xylene the cis substrate (1c) rearranged to a trans product [Fe2(CO)4(μ-3-t-BuC5H3GeMe2)2] 2t, while the trans substrate (1t) afforded a cis product 2c. This indicated that the rearrangement reaction is stereospecific, which is consistent with previous results. Molecular structures of 1c, 1t, 2t, and 2c were determinde by X-ray diffraction.