The molecular formula C5H6S may refer to:
- Methylthiophenes
- 2-Methylthiophene, an organosulfur compound that can be produced by Wolff-Kishner reduction of thiophene-2-carboxaldehyde
- 3-Methylthiophene, an organosulfur that can be produced by sulfidation of 2-methylsuccinate
- Thiopyran, a heterocyclic compound