Our HTE platform from Unchained Labs uses four distinct heating wells for reaction execution. We used two heating plates for each batch of HTE experiments in our ML optimisation workflow, constrained to two unique temperatures per batch. The experiments used to initialise the ML experimental workflow were selected using quasi-random Sobol sampling, restricting initial reaction temperatures to 70 and 100 degrees Celsius (see Supplementary Information section 5 for experimental procedures). All HTE reactions were evaluated using area percent (AP) yield. These yields, derived from Liquid Chromatography (LC), are uncorrected from differences in LC response factors between the Suzuki coupling product and the limited starting material. While approximate, AP yields provide a useful measure for elucidating reactivity trends and comparing performance of different reaction conditions .