Seliminski returned to Sliven in 1825. He opened a school in which he taught physics. His school became one of the first Bulgarian lower-level secondary schools.
On the eve of the Russian-Turkish War he organized many Bulgarians to support the Russian army. With the creation of revolutionary organizations in Sliven and some other cities, Seliminski became the first major Bulgarian revolutionary. After the war Seliminski participated in Russian delegations. Many Bulgarian people left their homes and emigrated to the other side of the Danube in Wallachia. Ivan Seliminski opened a school and was a teacher in New Sliven and Bucharest.