The paper is organized as follows. In Section 2, we discuss the general problem formulation of the experimental planning optimization problem, focusing on problems with discrete and mixedvariable design space. In Section 3, we review existing optimization methods for the target problem. Following that, in Section 4, we lay out the overall steps of PWAS, which we proposed to employ to address experimental planning optimization with mixedvariable domains. We then discuss the implementation and performance of PWAS through three case studies: Suzuki-Miyaura cross-coupling, crossed barrel, and reacting solvent design in Section 5. Conclusion and future research directions are summarized in Section 6.