The annual exhibitions attained a brilliancy and éclat hitherto unknown... Mr. Coates wisely established the schools upon a conservative basis, building almost unconsciously the dykes high against the oncoming flow of insane novelties in art patterns...

In this last struggle against modernism the President was ably supported by Eakins, Anschutz, Grafly, [Henry Joseph] Thouron, Vonnoh, and Chase... His unfailing courtesy, his disinterested thoughtfulness, his tactfulness, and his modesty endeared him to scholars and masters alike.

Coates commissioned The Swimming Hole from Eakins in 1884 as a work to be added to PAFA's permanent collection, only later to exchange it for the artist's Singing the Pathetic Song (1881).

[2] The nudity of the men in The Swimming Hole was unlikely to have bothered Coates, he and Eakins served as PAFA's representatives overseeing Eadweard Muybridge's photographic studies of the human body in motion.

Mrs. Coates was both inspired and encouraged by Arnold in her pursuit of writing poetry, which eventually led to the publishing of nearly three hundred poems in leading magazines and five volumes of collected verse.

[8][9] A funeral service was held at his Spruce Street house three days later, and he was buried at the Church of the Redeemer (Episcopal) churchyard in Bryn Mawr, Pennsylvania.

The inscription on Coates' headstone states, "High thought seated in a heart of courtesy", which was Phillip Sydney's description of an honorable man and gentleman.

On March 31, 1922, a "valuable collection of personal association books and first editions of English and American Authors" owned by Coates was sold at a Stan V. Henkels auction.