Sadiq Huseynov was born on 1 May 1883. In 1904, he finished Baku Vocational School and entered  Darmstadt Institute of Chemistry and Technology in Germany. He graduated in chemical engineering in 1910. In 1913, he entered  Kiev Medical Institute. He returned to Baku in 1917.

He was one of the founders of one-year qualification improvement courses for teachers in 1920. From 1920 to 1927, he chaired the Department of Chemistry, Azerbaijan Pedagogical Institute. Sadiq Huseynov lectured on chemistry at Azerbaijan Medical Institute and Azerbaijan Industrial Institute.

In 1927, he joined Baku State University, where he was appointed chair of the Department of Inorganic Chemistry. He then chaired the same department at Azerbaijan Medical Institute.

From 1921 to 1952, he taught chemistry at higher educational institutions.

In 1939, Sadiq Huseynov was made a professor, and received the title “Merited Scientist” in 1943. He put forward unique proposals for the production of iodine and bromine of well water, purification of sulfuric acid, synthesis of several valuable chemical compounds, and definition of value and quantity of some chemical elements.

During the WW Two, he invented new methods of producing some substances that were in high demand on the front.

His “Practical work in inorganic chemistry” in Azerbaijani language played a crucial role in educating several generations of chemists.