The reaction of 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-imine (Im DippNH) with trimethylsilylmethyllithium and anhydrous lutetium trichloride affords the imido complex [LuCl2(ImNDipp)(THF) 3] (1), which, on further reaction with dipotassium cyclooctatetraenide, K2(C8H8), leads to the half-sandwich cyclooctatetraenyl complex [(η8-C8H 8)Lu(ImNDipp)(THF)2]; both complexes contain very short Lu-N bond lengths, which are shorter than any previously reported Lu-N distances. © The Royal Society of Chemistry.