In the past decades, flowshops have been widely adopted to represent intra-organizational activities as well as inter-organizational relationships in the industrial networks. In this study, we provide lower bounds for two scheduling problems in two-stage hybrid flowshops. The problems under study are already known to be computationally challenging. To facilitate the development of branch-and-bound algorithms, we design lower bounds for the two problems. The lower bounds are derived based upon data rearrangement techniques. Computational experiments are designed and conducted to study the performances of the proposed bounds. Numerical results clearly evince the distinguished capability of the proposed bounds in curtailing unnecessary computation efforts for coping with the two problems under study.