The synthesis, structural and photophysical characterization, and theoretical studies on homo/heteroleptic neutral 2D-layered coordination polymers (CPs), obtained by combining the Er-III in ion with chlorocyananilate (ClCNAn) and/or tetrafluoroterephthalate (F4BDC) linkers, are herein reported. The structure of the heteroleptic Er-III-based CP, formulated as [Er-2(CICNAn)(2)(F4BDC)(DMSO)(6)](n) (1) is also reported. 1 crystallizes in the triclinic P1 space group, and the structure consists of neutral 2D layers formed by Er-III ions linked through the two linkers oriented in such a way that the neighboring 2D layers are eclipsed along the a axis, leading to parallelogram-like cavities. Photophysical measurements highlight the prominent role of chlorocyananilate linkers as optical antennas toward lanthanide ions, while wave-function-theory analysis supports the experimental findings, providing evidence for the effect of ligand substitution on the luminescence properties of homo/heteroleptic 2D CPs.