A new designed sonicated, continuous modular crystallizer was investigated and developed. The concept and design criteria for the designed crystallizer were examined and studied in a cooling crystallization process with three model compounds which were K2SO4, CuSO4, and phthalic acid. Results showed that ultrasound had significant effects, which can enhance the nucleation and avoid clogging in the tubular crystallizer. The present work shows the obtained results when different cooling strategies were studied. Equal supersaturation throughout the crystallization process was the best solution for designing temperature profiles for the modules. In addition to the cooling strategy, the residence time is one of the key factors to get feasible operating conditions in the designed crystallizer. Higher yields were obtained using ultrasound with phthalic acid crystallization, as a model compound, compared to a classical tubular flow reactor.