The authors report the growth of a II-VI ZnxCd1-xSe/Znx'Cdy'Mg1-x'-y'Se asymmetric coupled quantum well (asymmetric-CQW) structure that was used to investigate the active region of an intersubband electroluminescence structure designed for emission at lambda=4.5 mu m. Such a structure could comprise the active region of a quantum cascade laser. The results of photoluminescence and Fourier transform infrared spectroscopy analysis show good agreement with the expected transition energies predicted by simulation results for the asymmetric-CQW structure. High resolution x-ray diffraction analysis indicates high structural quality of the sample and good control of the growth. (C) 2008 American Vacuum Society.