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Treatment of SmI 2 (THF) n with the dilithium 1,4-diaza-1,3-diene (DAD) compound Li 2 -[(tBu)NCHdCHN(tBu)] (≡Li 2 (tBu-DAD); 2) prepared by reduction of tBu-DAD by 2 equiv of lithium in THF surprisingly results in the formation of the samarium(III) iodide complex [(THF) 2 Li(tBu-DAD)][(THF)Li(tBu-DAD)]SmI (5). The characteristic structural feature of 5 is formed by two (Z)-1,4-diaza-but-2-ene-1,4-diyl units bridging the Sm 3+ with two Li + ions. Complex 5 and the analogous chloride complex [(THF)Li(tBu-DAD)] 2 Sm(µ-Cl) 2 Li(THF) 2 (4b) react with 2 equiv of benzophenone to give the structurally very similar samarium complexes {[OC(Ph) 2 CH{CHdN(tBu)}N(tBu)]Li} 2 SmX(THF) (X ) Cl (6), I (7)) in high yield. The reaction formally proceeds via a 1,3-dipolar cycloaddition of the benzophenone CdO bond across a Sm-N-Cd fragment of the enediamide samarium complexes 4b and 5, including the formation of a new C-C bond, and results in the formation of the novel tripodal ligand [OC(Ph) 2 CH{CHdN(tBu)}N(tBu)] 2-. X-ray structure determinations of 6 and 7 revealed that the two tripodal ligands and the halogen atom form a slightly distorted octahedral coordination geometry around the Sm 3+ ion and that the Li + ions are retained within the ligand sphere by close contacts to their N and O atoms. By controlled hydrolysis of the cycloaddition product 6, the new tripodal ligands can be separated from the samarium and isolated in the form of the lithium compound {[OC(Ph) 2 CH{CHdN(tBu)}N(tBu)]Li} 2 (8). The crystal structure of 8, which is dimeric in the solid state, is reported.