Electronic spin in molecules of coordination compounds is promising as the basic logic unit of quantum computers. This technology will transform various aspects of society by enabling faster and more efficient computation, secure communication, and precise sensing. Molecules can be tailored to achieve specific magnetic properties through simple ligand substitution. Among the desired features is quantum entanglement, which interconnects the molecular quantum states for quantum information processing. Molecular crystals are formed through hydrogen bonds or other weak interactions between neighbor molecules, resulting in a structure that gives rise to spin lattices and spin-spin couplings. We will use electron spin resonance (ESR) to explain the crucial role of weak intermolecular interactions in determining the entanglement phenomenon in molecular crystals. A thorough understanding of these interactions is essential to successfully implement molecular crystals in future quantum devices.

Keywords
electron paramagnetic/spin resonance;ESR;transition-metal compounds;molecular magnetism; entanglement;quantum phase transition;