Emerging technologies aimed to tune properties of microporous materials, including zeolitic catalysts, involve microwave processing that accelerates chemical reactions and often increases efficiency of target materials. Here we report on the results of our comprehensive study of copper-exchanged mordenites obtained from sodium mordenite with Si/Al = 6.5 and CuSO₄ solution using both conventional and microwave assisted ion-exchange procedures. The current study confirms that microwave irradiation not only enhance the ion exchange but also is accompanied by a chemical reaction resulting in formation of an antlerite admixed phase, which explains the over-exchange of copper ions. Fourier transform infrared studies evidence epitaxial growth of antlerite on the surface of mordenite particles. Annealing at 450 °C leads to the transformation of antlerite into mesoporous CuO. Altogether it suggests that the resulting composite material obtained by the microwave assisted ion-exchange procedure can be considered as a promising catalyst with several different types of active sites.