Biochromophores are the tools that are used by nature in order to interact with visible light, and play the key element in phenomena such as photosynthesis, vision, pigmentation and bioluminescence. In order to understand the molecular basis of these phenomena, we are developing an action spectrometer which will allow to measure the photofragmentation and photoelectron spectrum of cold isolated biomolecular ions. This spectrometer will consist of a supersonic expansion ion source, a Wiley MacLaren accelerator, and an electrostatic ion beam trap with a nested photoelectron spectrometer - coupled with a femto-second laser system.