Compound 1 is comprised of [Bi4(3-O)2(POO)4(COO)4] SBUs which grow into a double wave-like 2D layer with —CH2CH2— spacers. <...> Compound 2 crystallizes in the orthorhombic noncentrosymmetric space group Pca21, exhibiting a double lattice-like layer. <...> Topological analyses indicate that 1 and 2 have sql (or Shubnikov tetragonal plane net) and kgd (or Shubnikov (3.6.3.6) plane net) topological networks respectively. 1 and 2 are isolated as single crystal pure phases, which is confirmed by powder XRD. <...> TGA shows high thermal stabilities with decomposition temperatures of 1 and 2 being 373 and 303 C respectively. <...> The recent decades have witnessed a flourish development in the research on coordination polymers or metal-organic frameworks (MOFs), due to not only the potential applications in functional materials, gas adsorption as well as catalysis, but their variety of intriguing structural architectures and topologies [ 1—6]. <...> One of the strategies to realize the construction of anticipative coordination polymers is the selection of metal ions, and organic ligands [ 7—9]. <...> However, it is still a great challenge to synthesize coordination polymers with predictable structures and properties [ 10, 11 ]. 2-Carboxyethyl(phenyl)phosphinic acid (H2CEPPA) was selected as our ligand not only for its use as reactive flame retardant [ 12 ], but for the structural features that it has owing to two formally analogous phosphinate and carboxylate moieties at both ends of a flexible alkyl —CH2CH2— spacer, and a phenyl group bonded to the phosphinate moiety [ 13, 14 ]. <...> Though there are only four O donor sites, the (H)CEPPA ligand with a flexible conformation can exhibit structural diversity even with the same dentate number [15—19 ]. <...> As compared to single carboxylate or phosphinate moiety, the phosphinate moiety bonded to an organic group can be readily designed as an asymmetric building block for second-order of NLO materials. <...> The existence of phenyl provides a high thermal and oxidation stability, and a negligible effect on the mechanical properties of the material. <...> H2CEPPA serves as a fully or partly deprotonated anionic ligand in the presented work. <...> Herein, we report the syntheses and structures of two 2D layered compounds [Bi2(3-O)(CEPPA <...>