The first Dickinson Hall (Architecture Catalog Entry), which stood near the site of the present entrance to Firestone Library, occupies a more a significant place in the university's academic than architectural development.

Commissioned in March 1869 and dedicated the following October, it was the first of the academic buildings erected under the leadership of President McCosh and the first structure at Princeton given over entirely to classrooms and lecture space. It was the product of the first collaboration between McCosh and John C. Green, Princeton's greatest benefactor of the 19th century.

Dickinson Hall, named for Princeton's first president, filled one of the pressing needs that McCosh had identified when he arrived in 1868: the lack of adequate classrooms. The opportunity to construct new classroom building also allowed McCosh to institute a simple but sweeping academic reform. In place of the old system, in which students stayed in the same recitation room for all their classes, the rooms in Dickinson were assigned to different professors according to their different branches of study.

In practice, this meant that students no longer were confined to the same room, but migrated from class to class. This also set the stage for McCosh to revamp the course of study and introduce more electives, particularly in the sciences.