|| New generation of radar systems will need to coexist with other radio frequency systems, anticipating their behavior and reacting appropriately to avoid interference. This has led to a flurry of recent activities in the SP community in the recent past, ranging from special sessions to special issues, dealing with architectures, waveforms, receivers, and performance assessment. With initial theoretical works achieving a certain maturity, there is a need to demonstrate the concept to lend credibility and attract the industrial actors. In light of this requirement, we plan to demonstrate the performance of intelligent spectrum utilization using a custom-built cognitive Multiple Input Multiple Output (MIMO) radar system employing optimized waveforms in the context of coexistence with communications. The optimized waveforms avoid the frequency bands occupied by communication links, while simultaneously having a small cross-correlation among each other to enable their separability at the MIMO radar receiver. We presented our first co-design prototype at SPAWC 2019 without the MIMO radar capability. In ICASSP 2020, we incorporated MIMO functionality to radar system, such as a new co-design waveform for an entire coherent processing interval of the radar, and range-Doppler estimation. In this new prototype, we have added a spectrum sensing application that identifies the occupied frequency bands on the fly and reports this information to the radar system. The MIMO radar system uses this information to optimize its waveform with up to 80MHz bandwidth in real time, offering enhanced performance for both radar and communications. We use the realistic LTE downlink for communications, and show the performance of system in real-time and over the air, by calculation of throughput for communications and the signal to noise (SNR) measurement for radar system. The developed prototype operates in real-time and over the air and we used 3 different USRPs from Ettus research and NI, namely, NI2974, NI2944, and B210 for LTE, cognitive MIMO radar, and spectrum sensing application, respectively. It also uses the LTE application framework with 20MHz bandwidth and flexibility in choosing MCS and resource blocks.