This study investigated the impact of a 10 kHz amplitude-modulation (AM) wave from a semiconductor microwave generator on the heating of ultrapure water and electrolyte aqueous solutions containing NaCl. It also examined the effects of AM waves on the yields of 4-methylbiphenyl (4-MBP) in the heterogeneous Suzuki-Miyaura coupling reaction, which was conducted in the presence of palladium nanoparticles supported on activated carbon (Pd/AC), as well as their influence on the growth rate during silver nanoparticle synthesis. Applying AM waves, typically used in telecommunications, enhanced heating efficiencies and improved product yields in both the chemical reaction and nanoparticle growth. Irradiating with microwaves under AM conditions allowed it to reduce power output while still achieving target yields and growth rates, even at the same temperatures without AM. This indicates the potential for highly efficient and energy-saving microwave processes in chemical reactions and material synthesis.