Five lanthanide(III) complexes of N‐(4‐phenylsulfonate)‐1,8‐naphthalimide (L₁) are described {[Ln(L₁)(DMSO)₅(H₂O)₂](L₁)₂ ⋅3H₂O where Ln(III)=Eu(III) (1), Tb(III) (2), Dy(III) (3), Ho(III) (4) and Er(III) (5)} . A structural, magnetic and photophysical study is reported for these complexes. The complexes feature a 1,8‐naphthalimide based anionic ligand, which is known for extending structure directing properties through π‐based interactions. Within these complexes L₁ acts as both a coordinating ligand as well as a non‐coordinating counter‐ion and overall the solid‐state structures adopt layered topologies that are achieved through π‐π interactions between L₁ molecules. Complexes of 1 and 2 display the characteristic line‐like emission profiles expected for Eu(III) and Tb(III) whilst the magnetic properties of the Dy(III) containing complex 3 were investigated.