A heteroleptic terminal alkyl lutetium complex stabilized by a bulky guanidinato ligand, LLu(CH₂C₆H₄NMe₂-o)(Me)(THF) (1) (L = (PhCH₂)₂NC(NC₆H₃ⁱPr₂-2,6)₂) has been synthesized by the treatment of LLu(CH₂C₆H₄NMe₂-o)₂ with AlMe₃ (1 equiv.) via an alkyl-exchange reaction in toluene/THF (4 : 1) solution and fully characterized. The difference in the activities of aminobenzyl and methyl was also proven through their selective reactivity, including complex 1 with one equivalent of DIC, CS₂ and HPPh₂, to afford complexes LLu[(NⁱPr₂)₂CMe](CH₂C₆H₄NMe₂-o) (2), L₂Lu₂[μ-η¹:η²-S₂CCHC₆H₄NMe₂-o][μ-η²:η²-S₂CCHC₆H₄NMe₂-o](THF) (4), and {LLu(Me)[μ-O(CH₂)₄ PPh₂]}₂ (5), respectively. The subsequent transformations have also been investigated, obtaining complexes LLu[(NⁱPr₂)₂CMe][(NⁱPr₂)₂C CH₂C₆H₄NMe₂-o] (3), {LLu[O(CH₂)₄PPh₂][μ-O(CH₂)₄PPh₂]}₂ (6) and dimeric lutetium phosphide {LLu[μ-O(CH₂)₄PPh₂]}₂(Me)(PPh₂) (7). In addition, the guanidinate bimetallic alkynyl-bridged lutetium complex [LLu(μ-CCPh)]₂(μ-η²:η²-PhC₄Ph) (8) bearing the μ₂-butatrienediyl group was obtained from the reaction of 1 with PhCCH (2 equiv.). The guanidinate lutetium μ-imido complex [LLu(μ-NPh)(THF)]₂ (10) was also obtained in good yield by the treatment of 1 with PhNH₂.