105 ILCS 5/10-21.5
The board of education of any community high school district, township high school district, consolidated high school district, or community unit district heretofore created shall within 4 years from the date of such creation establish within the district one or more high schools with a program of studies extending through the ninth to twelfth years, inclusive, and in such districts created hereafter the board of education shall within four years following the creation of the district establish such high schools.
Notwithstanding any other provision of this Act, any unit district that has a majority of its territory in the same county as a special charter district that, as authorized by Section 12-24, accepts tuition students in grades 9-12 from a neighboring unit district that does not maintain a high school may, by agreement between the school board of the unit district and the school board of the charter district, send its students in grades 9-12 to the charter district upon payment of such tuition and other terms as may be agreed by the boards.
Except as otherwise provided in Section 5-32, if the board of education fails to establish a high school as required by this section the district shall become automatically dissolved and the property and territory of such district shall be disposed of in the manner provided in this Act, provided that no community high school district shall be dissolved under this Act where an election has been held, a site selected, and bonds to construct a high school building have been sold prior to September 1, 1955.
105 ILCS 5/10-21.5