1：Experimental Design and Method Selection:

The study involved the synthesis of lanthanide complexes using Ln3+ ions and a N-heterocyclic dicarboxylic acid ligand. The structures were determined by single-crystal X-ray diffraction.

2：Sample Selection and Data Sources:

The reagents were used from commercial sources without further purification. The H2L was obtained from Jinan Camolai Trading Company.

3：List of Experimental Equipment and Materials:

Infrared (IR) spectra were collected on Bruker Equinox-55 FT-IR spectrometer. The thermogravimetric analyses (TGA) were performed on the NETZSCH STA 449C microanalyzer thermal analyzer. Elemental analyses were tested on PerkinElmer 2400C elemental analyzer. The powder X-ray diffraction (PXRD) data were obtained on Bruker D8 ADVANCE X-ray powder diffractometer. Solid-state luminescent spectra were collected by Hitachi F-4500 fluorescence spectrophotometer. Magnetic data were carried out by Quantum Design MPMS-XL-7 SQUID magnetometer. The UV?vis spectra were measured on Hitachi U-3310 spectrometer. The X-ray photoelectron spectroscopy (XPS) measurement were performed on AXIS Ultra spectrometer. The CO2 sorption isotherm was measured on Micrometrics ASAP 2020M.

4：0M. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The synthesis involved mixing H2L, Ln(NO3)3·6H2O, dimethylacetamide (DMA), and H2O in a Teflon-lined stainless steel vessel, kept at 95 °C for 72 h, and then cooled to ambient temperature. The crystal structures were isolated by cleaning with DMA and dried in air.

5：Data Analysis Methods:

The structures were refined anisotropically on F2 by a full-matrix least-squares refinement with SHELXTL program and OLEX2. The reflection data were corrected by SADABS program.