This article revisits the formation of 4-methylbiphenyl by the Suzuki-Miyaura reaction to examine the formation of hot spots and the factors impacting product yields, such as (i) mass transfer of reactants to the Pd/AC catalyst, (ii) continuous versus pulsed microwave irradiation, (iii) presence of a standing wave versus a nonstanding wave, and (iv) microwave input power levels. Present results indicate that mass transfer and hot spots impact the catalytic process. The rate of stirring of the heterogeneous mixture impinges on the formation of hot spots and product yields. Continuous and pulsed microwave have little effect, whereas both mass transfer and the presence or a absence of a standing wave do affect the yields. Beyond a certain stirring rate (1500 rpm), mass transfer is no longer an issue as yields remain constant; below this value, however, mass transfer, hot spots, and microwave input power levels play a role in the extent of products formed.