Combined theoretical and experimental techniques are developed to study light–matter interactions for participating media encountered in high-temperature solar thermal and thermochemical applications. The scope of research includes design and optimisation of an experimental radiative spectroscopy/radiometry facility and demonstrating its use to determine effective optical and radiative properties of various participating media types such as particle suspensions, packed beds, nano-, micro- and macro-structures, fibrous media, semi-transparent solids and liquids, and molecular gases. Inverse radiative transfer models are developed to infer the radiative and optical properties from measured overall characteristics such as the transmittance, reflectance, and emittance.