Reaction of hexanuclear octahedral molecular precursors with a 3-chlorobenzoate ligand affords an unprecedented family of isostructural polylanthanide complexes via solvothermal and microwave-assisted syntheses in an acetonitrile medium. The general chemical formula of the compounds that constitute this series is {[Ln6(μ3-OH)2(H2O)2(NO3)2(3-cb)14]·(CH3CN)4}, where 3-cb- stands for 3-chlorobenzoate and Ln = Eu, Tb, Dy, Ho, Er, or Y. The crystal structure, solubility, and magnetic and luminescent properties of these complexes have been studied. The luminescent properties evidence that the composition of the hexalanthanide precursor is preserved during the synthetic process that is of particular interest for cases in which heterolanthanide complexes are targeted.