Nanospheres of a new coordination polymer {[Cd 2 (µ-HL)(µ-L)(NO 3 ) 3 (H 2 O)]·H 2 O} n (1) were easily prepared by a sonochemical method from cadmium(II) nitrate and HL (HL, pyridine-2-carboxaldehyde isonicotinoyl hydrazone) in ethanol. Single crystals of 1 were also obtained using a branched tube method. The crystal structure of 1 indicates that the µ-HL/µ-L − blocks act as linkers between the Cd(II) centers, assembling them into 1D tooth-shaped interdigitated chains, which are further interlinked into a complex 3D H-bonded network with a rare hms (3,5-conn) topology. Nanoparticles of 1 were characterized by elemental analysis, FT-IR spectroscopy, and powder X-ray diffraction (XPRD), while their spherical morphology was confirmed by transmission electron microscopy (TEM). Furthermore, in the presence of a surfactant, the thermolysis of sonochemically generated nanoparticles of 1 led to the formation of cadmium oxide nanospheres (cubic CdO) with an average diameter of 10 nm. This study extends the application of sonochemical synthetic methods for the generation of phase pure nanoparticles of coordination polymers and their thermolysis products. nanoscale materials, the development of versatile, facile, and inexpensive methods for the preparation of nanocrystalline materials still remains a challenging area of research.Among a variety of strategies applied for the generation of nanoparticles, the sonochemical synthesis is particularly attractive, given its simplicity, cost effectiveness, quick reaction times, excellent yields, and purity of products [18,19]. Hence, in the past decade, ultrasonic irradiation has been applied for the synthesis of nanoparticles for a wide range of compounds [18][19][20][21][22][23][24][25][26][27][28]. In particular, synthesis of group 12 semiconductor nanoparticles (e.g., CdO, CdS, ZnO, ZnS) is of major interest, due to their size-and shape-dependent electronic and optical properties, as well as potential applications in light-emitting devices and nonlinear optics [29][30][31]. Cadmium oxide (CdO) is also an important inorganic semiconductor with a large band gap [32].On the other hand, coordination polymers (CPs) assembled from metal nodes and multidentate organic linkers can be used as precursors for a desirable type of nanoparticles. Such parameters as the composition, size and morphology of metal oxide nanoparticles can be influenced by selecting an appropriate type of metal-organic precursor, and tuning the experimental conditions. Interestingly, nanoscale CPs can also be applied for the preparation of nanomaterials with controlled particle size and uniform morphologies, and eventually more desirable properties [33][34][35][36].Considering all these points, and following our interests in crystal engineering, design of novel coordination polymers and derived functional materials [37-44], we focused our attention on developing a sonochemical synthetic approach for the preparation of a new cadmium(II) coordination polymer as a precursor for nanospheres of CdO. Another objective o...