Semiconductor devices are integral part of our lives. These devices have enormous impact on human lives. Even though there had been an extensive research on other semiconductor materials, no other material has revolutionized the microelectronic industry as Si. However, there are few limitations with Si as well. Si is an indirect bandgap semiconductor so it cannot be used as good light emitter or absorber. Interaction between photons and electrons is a major characteristic which all of the optoelectronic devices exhibit. Since direct bandgap semiconductor materials present strong emission/absorption characteristics, those are most suitable for optoelectronic devices. Compound semiconductor materials, which are formed by combination of group III and group V materials of the periodic table, are such direct bandgap materials. These are very crucial in the development of broad range of optoelectronic devices ranging from optical communications, visible and infrared lighting and imaging, high efficiency solar cells etc. Hence, this special issue will address the technological breakthroughs, development of state-of-art-devices, and challenges faced in the field of compound semiconductor optoelectronic device and process technology. This will enhance the knowledge spectrum of the reader of journal.