The path to an independent department at the Technical Faculty (1905-1924)
The period 1905-1924. includes preparation for the establishment of special classes for engineer-technologists, caused by the growing need for chemical and technological education of future engineers. In that period, at the then Mechanical and Technical Department of the Technical Faculty, the first permanent teachers were elected and the teaching of technological subjects was introduced, and in 1910 the Cabinet for Chemical Technology was established, which in 1912 changed its name to the Chemical and Technical Institute to keep it until 1961; the institute included laboratories for inorganic, analytical and organic chemistry. Two significant personalities marked this period: Eng. Dušan Tomić (1875-1947), who was appointed a teacher of mechanical technology in 1905, and Eng. Kosta Todorović (1876-1953), who in 1908 was appointed a teacher of chemistry, chemical technology and metallurgy, and then founded the Chemical Technical Institute. These two teachers significantly contributed to the introduction of special classes for engineers-technologists in the period 1925-1941. took turns in the position of head of the Technology Department.

As a consequence of the First World War, the University did not work in 1914-1919. further changes in the preparatory period did not occur until 1923, when a third, Technological, was established at the Mechanical and Electrical Engineering Department in addition to the two existing majors. With this decision, an important step was taken for the further development of these branches of technical sciences into independent departments and later into faculties. For the students of the new major, teaching orientation was carried out, which introduced teaching in specific, chemical and technological subjects, exercises in the chemical-technical laboratory and the preparation of a diploma thesis in technology.

At the end of 1923, special classes in chemistry were introduced at the Technical Faculty by appointing Dr. Aleksandar Leko (1890-1982), a significant figure in the development and work of the department, as a teacher, head of the department and dean until his retirement in 1961.