An Infrared-Ultraviolet Double Resonance (IR-UV DR) experiment has been built in order to resolve and identify single rotational levels in dense molecular spectra. The system is based on a CO laser, working on the CO fundamental transition (Δ v=1), and a frequency doubled dye laser pumped by a recently developed copper vapor “HyBrID ” or “CuHBr” laser. We demonstrate the promising nature of the CuHBr laser as a pump laser for high power dye lasers. Different excitation schemes can be used with this experiment in order to obtain information about excited electronic states. We also report here preliminary results on the spectroscopy of the carbon disulfide (CS 2) molecule.