With the rapid increase in performance and complexity of wireless networks, it has become challenging to build experimentation platforms that can meet such performance requirements but at the same time are comparatively easy to use and flexible. The lack of suitable platforms inspired us to build MIMORPH, a single experimentation platform that supports massive MIMO sub-6 GHz systems, ultra-high bandwidth Millimeter Wave (mmWave) MIMO, as well as mixed sub-6 GHz and mmWave configurations. It can be operated in a closed-loop manner and is intended for WLAN, 5G-NR and future 6G research. MIMORPH is built on top of standard components, such as a state-of-the-art RFSoC FPGA system and its implementation is made freely available to the research community.