Named in honor of one of the building's principal benefactors, this addition opened for classes the fall semester of 2008.  It is a newly constructed, state-of-the-art, 28,000 square foot facility with seven teaching laboratories for biology, chemistry, and biochemistry and a water analysis lab.  Off the spacious lobby are science faculty offices with a large outer office area for those students who serve as faculty assistants in the Work Program.  The building also contains a conference room and specimen display room.  The Mahan Wing is one of the first LEED (Leadership on Energy and Environmental Design) silver rated buildings in central Illinois bespeaking its environmentally conscious design.