Developed the first compiler and conducted work that led to the development of COBOL ?

Grace Hopper.

Explanation:

Grace Hopper was a US Naval Rear Admiral and an American computer scientist who was born on the 9th of December, 1906 in New York city, United States of America. She worked on the first commercial computer known as universal automatic computer (UNIVAC), after the second World War II.

In 1953 at the Remington Rand, Grace Hopper invented the first high-level programming language for UNIVAC 1 by using words and expressions.

Additionally, the high-level programming language known as FLOW-MATIC that she invented in 1953 paved the way for the development of common business-oriented language (COBOL).

Hence, Grace Hopper developed the first compiler and conducted work that led to the development of COBOL.