**3. Experimental**

#### *3.1. Chemicals & Equipment*

All chemicals were obtained from commercial sources. In particular, 3-(2,4-Dicarboxy lphenoxy)phthalic acid (H4dpa) was acquired from Jinan Henghua Sci. & Tec. Co., Ltd. (Jinan, China). Infrared (IR) spectroscopy measurements (KBr discs) were performed on a Bruker EQUINOX 55 spectrometer (Bruker Corporation, Billerica, MA, USA). Elemental analyses (C, H, N) were carried out on an Elementar Vario EL device (Elementar, Langenselbold, Germany). LINSEIS STA PT1600 thermal analyzer (Linseis Messgeräte GmbH, Selb, Germany) was used for TGA (thermogravimetric analysis) measurements under N2 atmosphere at 10 ◦C/min heating rate. Excitation/emission spectroscopic data were obtained using an Edinburgh FLS920 fluorescence spectrometer (Edinburgh Instruments, Edinburgh, England). Rigaku-Dmax 2400 diffractometer (Cu-K α radiation; *λ* = 1.54060 Å; Rigaku Corporation, Tokyo, Japan) was used to obtain powder X-ray diffraction (PXRD) patterns. Solution 1H NMR (nuclear magnetic resonance) spectra were measured on a JNM ECS 400M spectrometer (JEOL Ltd., Tokyo, Japan).

#### *3.2. Hydrothermal Synthesis & Analytical Data*

In a general procedure, metal(II) chloride (0.2 mmol: CuCl2·2H2O (34.1 mg) for **1**, MnCl2·4H2O (39.6 mg) for **2**, or ZnCl2 (27.3 mg) for **3**), H4dpa (0.1 mmol, 34.6 mg), bipy (0.2 mmol, 31.2 mg), NaOH (0.4 mmol, 16.0 mg), and H2O (10 mL) were added into a Teflonlined stainless steel vessel (volume: 25 mL) and stirred for 15 min at ambient temperature. Then, the vessel was closed and kept in an oven at 160 ◦C. After 3 days at this temperature, the vessel was gradually (10 ◦C/h) cooled down to ambient temperature. The reaction

mixture was then transferred to a glass flask and the crystals of products were decanted or filtered off, followed by washing with H2O and drying in air to produce compounds **1**−**3**.

*[Cu2(μ4-dpa)(bipy)2(H2O)]n*·*6nH2O (1).* Blue block-shaped crystals, yield: 55% based on H4dpa. Calcd for C36H36Cu2N4O16: C 47.63, H 4.00, N 6.17%. Found: C 47.86, H 3.98, N 6.21%. IR (KBr, cm<sup>−</sup>1): 3748 w, 3082 w, 1599 s, 1568 s, 1497 w, 1475 w, 1448 m, 1368 s, 1288 w, 1240 m, 1164 w, 1137 w, 1084 w, 1062 w, 1032 w, 974 w, 921w, 854 w, 823 w, 770 m, 735 w, 663 w.

*[Mn2(μ6*-*dpa)(bipy)2]n (2).* Yellow block-shaped crystals, yield: 52% based on H4dpa. Calcd for C36H22Mn2N4O9: C 56.56, H 2.90, N 7.33%. Found: C 56.37, H 2.89, N 7.38%. IR (KBr, cm<sup>−</sup>1): 1639 s, 1598 s, 1569 m, 1470 w, 1438 w, 1376 s, 1240 m, 1182 w, 1157 w,1128 w, 1087 w, 1063 w, 1013 w, 968 w, 923 w, 848 w, 820 w, 770 m, 736 w, 696 w, 675 w, 646 w.

*[Zn2(μ4-dpa)(bipy)2(H2O)2]n*·*2nH2O (3).* Colorless block-shaped crystals, yield: 48% based on H4dpa. Calcd for C36H30Zn2N4O13: C 50.43, H 3.53, N 6.53%. Found: C 50.64, H 3.55, N 6.51%. IR (KBr, cm<sup>−</sup>1): 3383 w, 3106 w, 1614 s, 1569 s, 1470 m, 1438 s, 1392 s, 1322 w, 1244 w, 1157 w, 1083 w, 1063 w, 1021 w, 972 w, 918 w, 877 w, 766 m, 733 w, 687 w, 650 w.

#### *3.3. Single-Crystal X-ray Diffraction*

For CPs **1**–**3**, data were collected on a Bruker APEX-II CCD diffractometer (Bruker, Karlsruhe, Germany) (graphite-monochromated Cu*K*α radiation, *λ* = 1.54178 Å). SADABS was used for semi-empirical absorption corrections. Crystal structures were determined by direct methods, followed by the refinement (full-matrix least-squares on *F<sup>2</sup>*) with SHELXS-97 and SHELXL-97 [40]. With an exception of hydrogen atoms, all other atoms were subjected to an anisotropic refinement (full-matrix least-squares on *F*2). Except hydrogen atoms in water, all H atoms were placed in calculated positions (fixed isotropic thermal parameters); these were taken into account at the final stage of full-matrix least-squares refinement in structure factor calculations. Water hydrogen atoms were found by difference maps and constrained to the respective oxygen centers. In **1**, some molecules of solvent are heavily disordered and thus were detached by applying SQUEEZE in PLATON [41]. Elemental and thermogravimetric analyses confirmed the number of crystallization H2O molecules. For **1**–**3**, final crystal data are summarized in Table 3. Representative bond distances and angles (Table S1) as well as hydrogen bond parameters (Table S2) are listed in Supplementary Materials. CCDC-2043757–2043759 contain crystallographic data for **1**–**3**.

For topological analysis of 2D layers in **1**–**3**, an underlying net concept was followed [42]. Such simplified networks were constructed by reducing bridging ligands to their centroids and removing terminal ligands, preserving a ligand–metal center connectivity.
