[3] Hill was an analytical chemist, designing spectroscopic methods and developing ways to track the progress of the reactions based on solubility.

[5] Hill also undertook graduate study at the University of Pennsylvania in the summers, awarded the first master's degree in chemistry to an African-American woman in 1941.

[1] The Hills used Grignard reagents to develop chemical syntheses of ketenes, which was funded by grants from the National Science Foundation (NSF) and the U.S. Air Force.

[1][9][10] Her methods were used to determine the solubility of different components in non-aqueous solutions, which enabled synthetic chemists in their group to identify, isolate, and quantify products.

[1][6] Mary Hill instituted student chapters of the American Chemical Society at some of the historically black colleges and universities where she taught.

[10] In a 1963 newspaper interview, hobbies mentioned were reading, studying German and Russian, and enjoying flower arranging and watching football.

[1] The Hills had just returned from a trip to England, when Mary died from "a heart condition" she had "for some time",[4] in King's Daughters Hospital in Frankfort, Kentucky[13] on February 12, 1969.