The syntheses, characterization, structures, and properties of a series of Ln(III) coordination polymers with a flexible bis(sulfinyl) ligand, 1,4-bis(phenylsulfinyl)butane (L), are reported. Unique noninterpenetrated two-dimensional (4,4) nets are formed in these complexes. The coordination number of the Ln(III) ions across the whole Ln(III) series remains unchanged, and all the complexes of this series are isomorphous and isostructural. The perchlorate anions may set as a template in the formation of these unique square arrays, and the counteranions may be a key factor in controlling the structures of such complexes.