This work presents the synthesis and characterization of a 3d-4f bimetallic complex based on the redox-active macrocyclic biquinazoline ligand, Mabiq. The mixed Yb-Ni complex, [(Cp*)(2) Yb(Mabiq)Ni]BArF (3), was synthesized upon reaction of [Ni-II (Mabiq)]3ArF (2) with (Cp*)(2) Yb-II (OEt2). The molecular structures of 3 and its sister complex, [(Cp*)(2) Yb(Mabiq)Ni][(Cp*)(2) Yb-(OTf)(2)] (1), confirmed the presence of a Yb(III) center and a reduced Ni-Mabiq unit. Spectroscopy (absorption and NMR), cyclic voltammetry, and magnetic susceptibility studies were employed to analyze the electronic structure of 3, which is best described by the [(Cp*)(2)Yb-III(mabiq center dot)Ni-II](+) formulation. Notably, the ligand- centered radical is delocalized over both the diketiminate and bipyrimidine units of the Mabiq ligand. The magnetic susceptibility and variable temperature NMR studies for 3 denote coupling between the Ni-Mabiq site and the peripheral Yb center-previously unobserved in 3d-3d Mabiq complexes. The complex nature of the exchange interactions is highlighted by the multiconfigurational ground state for 3, comprising nearly degenerate singlet and triplet states.