II–IV–V2 materials offer the promise of enhanced functionality in optoelectronic devices due to their rich ternary chemistry. In this review, we consider the potential for new optoelectronic devices based on nitride, phosphide, and arsenide II–IV–V2 materials. As ternary analogs to the III–V materials, these compounds share many of the attractive features that have made the III–Vs the basis of modern optoelectronic devices (e.g. high mobility, strong optical absorption). Control of cation order parameter in the II–IV–V2 materials can produce significant changes in optoelectronic properties at fixed chemical composition, including decoupling band gap from lattice parameter. Recent progress has begun to resolve outstanding questions concerning the structure, dopability, and optical properties of the II–IV–V2 materials. Remaining research challenges include growth optimization and integration into heterostructures and devices.