Abstract The synthesis of seven endohedral metallocenophanes of rhodium (7b, 8b) and cobalt (1d− h) with a cyclopentadienyl unit as one of the π-systems and a cyclobutadiene or cyclopentadienone unit as the second π-system is described, including the synthesis of the unsubstituted parent compound of the [CpCo (cbd)]-derived endohedral phanes,[3.3]-η 5-(1, 1', 3, 3')-cyclopentadienyl–η 4-(cyclobutadienophane) co-balt (I)(1h). This compound ...