In 1779, Bouligny and his son José Eliodoro, arrived in Constantinople. Bouligny sought an agreement based upon the treaty of trade and friendship the sultan signed with the Kingdom of the Two Sicilies in 1740, but the negotiations were long and drawn out, as well as complicated by the need to rely on non-Spanish dragomans as interpreters and go-betweens. However, an agreement was finally signed between Spain and the Ottomans on 14 September 1782, and Bouligny was officially installed as Spain's extraordinary envoy and plenipotentiary minister to the Sublime Porte. As envoy, he worked to establish a Spanish consular network within the empire and a school to train Spanish boys in Turkish language and culture to serve as dragomans. He also made careful notes about the mercantile activities of traders from across Europe in Constantinople, both to report back to Spain and to strengthen his business interests in the region. Bouligny left Constantinople in 1793, leaving his son to oversee the family's mercantile operations. The younger Bouligny continued to serve as Spain's representative to the Ottomans until he was expelled in 1799 following the invasion of Egypt by Spain's ally France.