In the present study of nano-sized strontium-doped lanthanum manganite, La0.75Sr0.25MnO3 (LSM), were synthesized by three simple, different methods (co-precipitation, ultrasonic and microwave-assisted co-precipitation) from a lanthanum(III) coordination polymer, [pyda.H]2[La2(pydc)4(H2O)4].2H2O, where [pyda.H]+ = 2,6-diaminopyridinium, and [pydc]2- = 2,6-pyridinedicarboxylate, as a new precursor. The products are characterized through Fourier transformed infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), a field emission scanning electron microscope (FESEM), thermal gravimetric (TG) and differential thermal analyses (DTA), and Energy-dispersive X-ray spectroscopy (EDX). The XRD results exhibited that the crystal lattice of the products were obtained an orthorhombic perovskite structure. The porosity, particle size and homogeneity of LSM calcinated strongly dependent on the preparation methodology. In addition, the results approve that the formation time is decreased considerably by ultrasonic or microwave irradiation.