Marilyn was an international leader in the crystallographic study of fullerenes or Buckyballs – a sphere-shaped, crystalline allotrope of carbon discovered in 1985. In conjunction with Professor Alan Balch, who became a lifelong friend, she co-pioneered a technique to co-crystallize fullerenes in a manner that would allow for superior structural data than standard crystallization methods. She utilized this technique to elucidate the structures of numerous new, higher or endohedral fullerenes. Marilyn was the first person in the world to characterize with X-ray crystallography an endohedral metallofullerene and a non-IPR obeying endohedral metallofullerene. This work was central to the Ph.D. dissertations of dozens of students co-advised by Balch and Olmstead. In addition to her expertise in the field of fullerene research, her crystallographic prowess impacted and spurred breakthroughs in research relating to coordination chemistry, organometallic chemistry, organic synthesis, and solid-state inorganic chemistry. She was a visiting scholar at research institutes in numerous countries, including Malaysia, China, Germany, Great Britain, India, and Switzerland.