Two inorganic-organic hybrid materials based on β-[Mo₈O₂₆]⁴⁻, namely {[Ni(b-Mo₈O₂₆)(H₂O)₄] (H₂Fbix) 2H₂O_n (1), {[Co(b-Mo₈O₂₆)(H₂O)₄] (H₂Fbix) 2H₂O}_n (2) (Fbix = 2,3,5,6-tetrafluoro-1,4-bis(imidazol-1-ylmethyl)benzene)) were hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, power X-ray diffraction, infrared spectroscopy, thermogravimetric analysis and elemental analysis. Single crystal X-ray analysis reveals that 1 and 2 are isostructural. Take 1 as an example, each six-coordinated Ni^II ion is surrounded by two β-[Mo₈O₂₆]⁴⁻ units and four water molecules, forming an inorganic anionic linear chain. Protonated H₂Fbix ligands act as guest and balance the charge of anionic framework. The inorganic chain [Ni(b-Mo₈O₂₆)(H₂O)₄]_n^2n–, H₂Fbix ligand and water guest molecules were further connected by hydrogen bonds to generated the final 3D structure. Both compounds 1 and 2 can serve as heterogeneous catalysts and show good photocatalytic activity for the degradation of MB dye under UV irradiation. Additionally, the catalyst could be easily recovered and reused four times without significantly loss for its crystallinity and activity.