Jean Émile Charles Timmermans (8 January 1882 – 27 August 1971)[1] was a Belgian physical chemist and educator. He was known for the discovery of plastic crystals[2][3] and the published books on physical chemistry constants and experimental data of pure solutions. He also curated the work of Belgian chemist Jean Stas. Timmermans was a member of the Brussels school of thermodynamics[4] centered around Brussels and one of the mentors of Nobel laureate Ilya Prigogine.[5]