A new era in the study of Earth-like planets in exosolar systems has provided a fundamental and new impetus for understanding the evolution of planetary systems, placing traditional comparative planetology focused on our own system in a much broader context and a wide range of possible variability. Against this background, the study of our sister planet Venus in comparison to Earth is becoming increasingly important. Venus provides a laboratory for comparative planetology, with important insights into the sensitive effects of stellar environmental conditions on the evolution of habitable planets. A number of space missions to Venus, planned and under development, reflect this approach to comparative planetology in the Solar System and its application to understanding global stellar planetary systems. This article evaluates and classifies the planned Venus investigations using infrared and ultraviolet spectroscopy in terms of their ability to answer these questions. The article is based on known data from missions such as Venera 15/PMV (RU), VIRTIS, SPICAV and SPICAV-SOIR/VEX (ESA), and MERTIS (ESA), as well as many others in which the authors have been involved. We report on the key questions concerning the evolution of Venus, and the contribution of infrared and ultraviolet spectroscopy, and reflect on them in the light of planned space missions.