A series of lanthanide-based cluster organic frameworks, [Ln(7)(μ(3)-OH)(8)L(9)(H(2)O)(6)]·4ClO(4)·3HL·nH(2)O [HL = 4-pyridin-4-ylbenzoic acid; Ln = Y (1), La (2), Gd (3), Yb (6), n = 6; Ln = Dy (4), Er (5), n = 4], were hydrothermally made and characterized. It is the first example of heptanuclear trigonal-prismatic lanthanide clusters via a hydrothermal reaction. The magnetic properties of 3 and 4 show typical antiferromagnetic interactions.