| Stefan Niementowski | |
| Birth Date: | 4 August 1866 |
| Birth Place: | Zhovkva, Poland now Ukraine |
| Death Place: | Warsaw, Poland |
Stefan Niementowski (August 4, 1866 - July 13, 1925 was a Polish chemist. He discovered the Niementowski quinoline synthesis and the Niementowski quinazoline synthesis.[1] He was a president of Polish Copernicus Society of Naturalists (1920–22).