Optical pump / terahertz probe spectroscopy determines the conductivity of a material on picosecond to nanosecond timescales after photoexcitation, and in a non-contact manner. It is ideal to examine the intrinsic photoresponse of semiconductor nanomaterials, without the complication of device fabrication. Further, it permits the formation of bound and free charges, and their subsequent transport and interaction with interfaces, to be tracked with exquisite detail. This provides us with important insights into charge transport in materials of significant interest, such as monolayer semiconductors and their heterostructures, nanowires, and materials for photovoltaics or photocatalytic processes such as solar water splitting. Other modalities provided by the facility also contribute to this theme, for instance infrared pump-probe studies of defect states in semiconductors, or transient absorption and transient bleaching processes, using our TVAS and TEAS beamlines.