A new imidazolidine-bridged bis(phenol) [ONNO]H-2 ([ONNO]H-2 = 1,4-bis(2-hydroxy-3,5-di-tert-butyl-benzyl)imidazolidine) was prepared in relatively high yield by Mannish reaction of 2,4-di-tert-butylphenol, formaldehyde, and ethylenediamine in a 2:3:1 molar ratio. Reaction of the bis(phenol) with NaH in THF, after workup, afforded the sodium bis(phenolate) {[ONNO]Na-2(THF)(2)}(2)center dot 2THF (1) as a dimeric tetranuclear complex in an almost quantitative yield. Reaction of YbCl3 with complex 1 in a 2:1 molar ratio in THF, in the presence of HMPA, produced the desired bis(phenolate) ytterbium dichloride as bimetallic complex [ONNO]{YbCl2(HMPA)}(2)center dot 2.5C(7)H(8) (2). Complex 2 can be used as a precursor for the synthesis of ytterbium derivatives by salt metathesis reactions. Reaction of complex 2 with (NaOPr)-Pr-i in a 1:2 molar ratio in THF led to the formation of bimetallic alkoxide [ONNO]{Yb(mu-(OPr)-Pr-i)Cl(HMPA)}(2)center dot THF (3). However, the residual chlorine atoms in complex 3 are inactive for the further substituted reaction. Further study revealed that the bulkiness of the reagent has profound effect on the outcome of the reaction. Complex 2 reacted with bulky NaOAr (ArO = 2,6-di-tert-butyl-4-methylphenoxo) or NaNPh2 in a 1:2 molar ratio under the same reaction conditions, after workup, to give the ligand redistributed products, (ArO)(2)YbCl(HMPA)(2) (4) and [ONNO]YbCl(HMPA)(2) (5) for the former and complexes 5 and (Ph2N)(2)YbCl(HMPA)(2) (6) for the latter. If the molar ratio of complex 2 to NaNPh2 decreased to 1:4, the expected ligand redistributed products [ONNO]YbNPh2(HMPA) (7) and (Ph2N)(3)Yb(HMPA)(2)center dot C7H8 (8) can be isolated in high yields. All of the complexes were well characterized, and the definitive molecular structures of complexes 1-4, 7, and 8 were provided by single-crystal X-ray analysis.