This african-american was killed in the boston massacre in 1770 and bears the distinction of being the first martyr of the american revolution. who was he?

The man described in the question is Crispus Attucks.

Crispus Attucks was among a huge group of American colonists who were protesting against the passage of the Townshend Acts. These acts put taxes on several important resources such as lead and paper. The colonists protesting this act were face to face with British soldiers who were trying to bring order to the city. This scene turned violent at one point and resulted in the shooting/killing of Crispus Attucks, making him the first death of the American Revolution.

 The answer Is Crispus Attucks