In the fine chemical industry, exothermic liquid-liquid reactions are commonly carried out in semibatch reactors (SBRs). It has been an essential issue to design thermally safe and productive operations for isoperibolic liquid-liquid SBRs. Because it is time-consuming and money-consuming to determinate accurate kinetic parameters, a kinetic-parameter-free approach for this issue is highly desired. In this work, we find that once MTSR in the isothermal liquid-liquid SBRs increase with the increase in the reaction temperature, the corresponding isoperibolic liquid-liquid SBRs with the jacket temperature being not lower than the isothermal reaction temperature must be in the QFS scenario. On the basis of this finding, a kinetic-parameter-free approach has been developed to design thermally safe and productive operating conditions for isoperibolic liquid liquid SBRs.