The Curiosity rover discovered various organic molecules in drill samples taken on Mars. Some of the identified molecules include thiophenes, benzene, toluene, and small carbon chains like propane or butene. Chlorine from perchlorate may have combined with fragments from precursor organic molecules when the sample was heated. The organic molecules and volatiles found are comparable to samples of sedimentary rock rich in organics on Earth. Methane, another organic molecule, has also been detected in the Martian atmosphere, with seasonal variations observed. Aromatic six-carbon molecules like chlorobenzene were also found in samples. These findings suggest the presence of chemical building blocks for life on Mars, though they do not confirm the existence of life itself. For more detailed information, you can refer to sources like Carnegie Science, NASA JPL, and CNN.