Michael Roman Wasielewski (born June 7, 1949) is an American physical chemist.
He is currently the Clare Hamilton Hall professor of chemistry, director of the Argonne-Northwestern Solar Energy Research Center, executive director of the Institute for Sustainability and Energy, and executive director of the Solar Fuels Institute at Northwestern University.Wasielewski is known for his research on light-driven charge transfer and transport in molecules and materials, photosynthesis, nano scale materials for solar energy conversion, spin dynamics of multi-spin molecules, molecular materials for optoelectronics and spintronics, and time-resolved optical and electron paramagnetic resonance spectroscopy.