In this study, three mesoporous nanopolymers, namely, [Ln(2,5-pydc)(2-pydc)]n (Ln = Sm (1), Nd (2) and Eu (3), 2,5-pydc = 2,5-pyridinedicarboxylic acid) have been synthesized under hydrothermal conditions. The synthesized coordination polymers were characterized by the elemental analysis, inductively coupled plasma (ICP), fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), single crystal X-ray diffraction and powder X-ray diffraction (PXRD) analysis. For morphological analysis, field emission scanning electron microscopy (FESEM) and brunauer, emmett and teller (BET) were used. The compounds are isostructural and lanthanide complexes contain three-dimensional infinite Ln-O-Ln chains. Photoluminescence properties and thermal stabilities of the compounds have been investigated. All the polymers showed high thermal stability. The polymers 1-3 exhibit luminescent emission bands at 624, 579 and 606 nm at room temperature when excited at 320 nm, respectively.