Macklin is most famous for his Poet's Gallery, a project he announced on 1 January 1787. He planned to commission 100 paintings illustrating famous English poems, which he would publish monthly as engravings between 1790 and 1795. He also held an annual exhibition in Pall Mall, like John Boydell and his Shakespeare Gallery. However, the war with France cut into his profits, as prints could not be traded across the channel, and his partner, Edward Rogers, died. The project produced paintings by Joshua Reynolds, Henry Fuseli, Thomas Gainsborough, John Opie, Angelica Kauffman, Thomas Stothard, and Francis Wheatley. Francesco Bartolozzi engraved many of the prints.