A synthetic strategy is developed to attach semirigid lipophilic sidearms to the 6-positions of bent aromatic tridentate 2,6-bis(benzimidazol-2-yl)pyridine cores to produce U-shaped ligands, L-6,L-7. Differential scanning calorimetry (DSC) reveals that entropic contributions severely affect the isotropization processes of these flexible receptors, but no mesomorphism is detected. The attachment of oxygen linkers to the 5- or 6-positions of the benzimidazole sidearms lowers the ligand-centered (1)pi pi* and (3)pi pi* excited states, and the semiempirical ZINDO method assigns this effect to a destabilization of the HOMO orbitals resulting from pi -interactions. Reactions of L6 With Ln(NO3)(3)(.) xH(2)O provide the rodlike 1:1 complexes [Ln(L-6)(NO3)(3)] (Ln = La-Lu), which are stable in the solid state but partially dissociate in acetonitrile. The crystal structure of [Lu(L-6)(NO3)(3)]. CH3CN (18a, LUC63H84N9O13, monoclinic, P2(1)/n, Z = 4) reveals an I-shaped arrangement of the ligand strand arising from the meridional complexation of the bent tridentate unit to nine-coordinate Lu(III). The replacement of nitrate anions with trifluoroacetate anions gives the centrosymmetric dimer [Lu(L-6)(CF3CO2)(3)](2) (23, Lu2C134H162N10O20F18, triclinic, P (1) over bar, Z = 1), in which the symmetry-related Lu atoms are connected by two bridging carboxylates, leading to an II-shaped dimetallic edifice. These complexes [Ln(L-6)(NO3)(3)] and [Ln(L-6)(CF3CO2)(3)](2) fulfill the geometrical criteria required by precursors of calamitic metallomesogens, but no mesomorphism can be detected, while photophysical studies indicate that the low energies of ligand-centered (3)pi pi* excited states drastically limit the luminescence of Eu(III) complexes. The relationships between structural and electronic properties resulting from 5- or 6-substitutions of the benzimidazole rings and the effects of these substitutions on photophysical and thermal properties are discussed.