Diliman Educational Foundation Inc. was duly registered with the Securities and Exchange Commission (SEC) on February 10, 1969. The company was organized to establish and operate an institution of learning which will give instruction in art, science, and other professional studies as prescribed by the government for nursery, kindergarten, and elementary levels.
On October 27, 1967, the SEC approved the Amended By-Laws of the corporation changing the company's name to Diliman Educational Corporation (DEC) to include the secondary level and post-secondary level which offers special and technical courses.
In 2002, DEC amended its by-laws to reflect its two operational units, Diliman Preparatory School (DPS) and Diliman Computer Technology Institute (DCTI) under which the basic education program and technical-vocational livelihood program are offered respectively.
In 2008, the Commission on Higher Education (CHED) granted the DCTI its permit to offer a Bachelor of Science in Information Technology, a Bachelor of Science in Business Administration, Bachelor of Elementary Education, and Bachelor of Secondary Education in 2010. This led to an amendment of the By-Laws for a name change from DCTI to Diliman College (DC) on September 8, 2014.
Diliman Preparatory School and Diliman College had become an educational landmark with its complex of a four-story building, two gymnasia, and three swimming pools, all situated on 10,200 square meters along Commonwealth Avenue in Quezon City.