2D molecular crystals (2D MCs) are an emerging family of 2D materials formed by organic or inorganic molecules held together entirely by weak intermolecular forces. 2D MCs are gaining attention in electronics and optoelectronics due to their structural diversity, scalability, and strong light-matter interactions. This review provides a comprehensive overview of 2D MCs and their potential in electronic and optoelectronic applications. It begins by highlighting the structural features and properties of key 2D MCs discovered to date, focusing on three strategies to manipulate intermolecular forces for better control over crystal morphology and properties. Then various methods are explored for fabricating large-area, highly-oriented 2D MCs, with an emphasis on vapor-phase and liquid-phase techniques. Last, their applications are reviewed in electronic and optoelectronic devices, such as channel materials, photosensitive components, and dielectrics. It is concluded by discussing future challenges and opportunities in the field, offering insights into scalable production and industrial applications of 2D MCs.