with dichlorobis(dimethylamino)diborane(4) with formation of bis(dimethylamino)bis(1-indenyl)-diborane(4) which rearranges on heating to the isomer bis(dimethylamino)bis(3-indenyl)diborane(4). The mixed isomer bis(dimethylamino)(1-indenyl)(3-indenyl)diborane(4) was obtained from indenyllithium and chlorobis(dimethylamino)(3-indenyl)diborane(4). Crystal data of 1,2-bis(dimethylamino)-1,2-bis(1-indenyl)diborane(4)