During this period, he worked with Da Ponte and met Antonio Salieri, who suggested that Mazzolà could write the libretto for an opera buffa entitled La scuola de' gelosi which premiered in 1778.
Later that year he significantly revised Metastasio's text for Mozart's new setting of La clemenza di Tito (originally created in 1734, on a music by Antonio Caldara).
Da Ponte and Salieri had suggested that Mazzolà would be a suitable poet for Count Rosenberg, the court theatre director.
In 1796, he returned to Venice, but Friedrich August III of Dresden helped Mazzolà to engage in diplomatic work, and requested that some of his writings should be sent back to the Saxon court each year.
[3] Mazzolà's librettos are mostly opere buffe and set by the Dresden composers Johann Gottlieb Naumann, Joseph Schuster and Franz Seydelmann.