A sonochemical method was used to synthesize a new nano Pb(II) 1D metal–organic zigzag chain [Pb(p-2-einh)NO2]n (1) (p-2-einh = (1-(pyridin-2-yl)ethylidene)isonicotinohydrazide). The compound was characterized by scanning electron microscopy (SEM), transmission electron microscopy, elemental analysis, IR spectroscopy, thermogravimetric analysis, X-ray powder diffraction, and single-crystal X-ray analysis. The X-ray analysis reveals a 1D zigzag-chain metal–organic polymer structure for 1 that is further extended to a 3D supramolecular structure by—interaction and other labile interactions. A coordination number of six was determined for the Pb(II) ions in PbN3O3. Lead oxide nanoparticles were prepared at 180 °C by thermolysis of 1. The average diameter of the nanoparticles was 20 nm. The size and morphology of the PbO samples were observed using SEM, and the structure of the system was optimized by DFT calculations. The calculated structural parameters and FT-IR spectra are consistent with the crystal structure.