This review discusses the emerging applications of semiconducting two-dimensional transition metal dichalcogenides (TMDCs) in various electronic and optoelectronic devices. TMDCs, with their two-dimensional structure and direct band gaps in the visible spectrum, are promising for digital electronics and optoelectronics. The review highlights the unique physical properties of TMDCs, such as crystal structure, symmetry, and thickness-dependent electronic and phonon structures. It also covers the development of field-effect transistors (FETs), heterostructure junctions, photodetectors, photovoltaics, and sensors based on TMDCs. The performance of these devices is compared with competing technologies, identifying both their merits and shortcomings. The review emphasizes the potential of TMDCs in flexible, stretchable, and transparent electronics, as well as the challenges in achieving high-quality, large-area substrates and improving light absorption and fluorescence quantum yields for optoelectronic applications. The gate tunability of heterostructure devices is highlighted as a unique advantage, enabling novel charge transport phenomena and dynamic tailoring of device characteristics.This review discusses the emerging applications of semiconducting two-dimensional transition metal dichalcogenides (TMDCs) in various electronic and optoelectronic devices. TMDCs, with their two-dimensional structure and direct band gaps in the visible spectrum, are promising for digital electronics and optoelectronics. The review highlights the unique physical properties of TMDCs, such as crystal structure, symmetry, and thickness-dependent electronic and phonon structures. It also covers the development of field-effect transistors (FETs), heterostructure junctions, photodetectors, photovoltaics, and sensors based on TMDCs. The performance of these devices is compared with competing technologies, identifying both their merits and shortcomings. The review emphasizes the potential of TMDCs in flexible, stretchable, and transparent electronics, as well as the challenges in achieving high-quality, large-area substrates and improving light absorption and fluorescence quantum yields for optoelectronic applications. The gate tunability of heterostructure devices is highlighted as a unique advantage, enabling novel charge transport phenomena and dynamic tailoring of device characteristics.