Coordination polymers (CPs) and metal–organic frameworks (MOFs) have emerged in recent decades as highly attractive classes of hybrid materials due to their unique structural and functional properties. Constructed by linking metal ions or clusters with organic ligands into one-, two-, or three-dimensional networks, these materials combine crystallinity, porosity, and tunable surface chemistry. Their potential in gas storage and separation, drug delivery, luminescent sensing, proton conduction, and, most importantly, heterogeneous catalysis, has made them the subject of extensive research worldwide. In the present study, we focused on the design, synthesis, and characterization of novel coordination polymers based on meta-phosphonobenzoic acid and 4,4ʹ-bipyridine ligands coordinated with Cu(II) and Co(II) ions. A combination of solvothermal and sonochemical methods was employed to achieve both high-quality single crystals and nanoscale materials under optimized conditions. The synthesized compounds were thoroughly characterized using a wide range of analytical and spectroscopic techniques. Single-crystal X-ray diffraction provided detailed crystallographic information, revealing diverse topologies and coordination environments around the metal centers. Fourier-transform infrared spectroscopy confirmed the presence of functional groups and bonding interactions, while scanning electron microscopy was used to study morphological features of the nano- and microcrystals. Energy-dispersive X-ray spectroscopy further verified the elemental composition, Brunauer–Emmett–Teller analysis determined surface areas and pore size distributions, and thermogravimetric analysis established the thermal stability of the frameworks. Hirshfeld surface analyses highlighted the significance of intermolecular interactions, such as hydrogen bonding and π–π stacking, in stabilizing the frameworks. Beyond structural characterization, the catalytic properties of selected nanocatalysts were evalu