Discrete lanthanide(III) tetranuclear cubane-like clusters seldom occur throughout the Ln(III) series and behave as single-molecule magnets (SMMs). Herein, a series of cubanes, [Ln(4)(mu(3)-OH)(4)(mu-tfa)(4)(hfa)(4)(phen)(4)] (1-9, Ln = La-Dy (except Pm), tfa = trifluoroacetate, hfa = hexafluoroacetylacetonate, phen = 1,10-phenanthroline), and dinuclear clusters, [Ln(2)(mu-OH)(2)(hfa)(4)(phen)(2)] (10-16, Ln = Tb-Lu), were synthesized and characterized. Two types of clusters were formed due to the change of preferred coordination geometry for lighter and heavier Ln(III) ions which favor nine-coordinated cubanes and eight-coordinated dimers, respectively. A magnetic study shows that 8-Tb-4 and 9-Dy-4 are ferromagnetically coupled and SMM in nature because of the larger Ln center dot center dot center dot Ln distance compared to other discrete cubanes. The anisotropic barriers, U-eff, of 9-Dy-4 are determined to be 67.0 K. In addition, the photophysical properties of 6-Eu-4, 8-Tb-4, and 10-Tb-2 owing to tfa, hfa, and phen sensitization and O-H quenching are discussed.