The new discovery indicates towards the presence of life on red planet 3 billion years ago.
Carbon, which is the primary ingredient of coal was also found to be in roughly the same quantities as those observed in Martian meteorites found on Earth, and about 100 times greater in concentration than prior detections of organic carbon on Mars' surface.
The details about the research will also be published on Thursday in Science- which is one of the top scientific journals.
Organic molecules are mainly linked with biological life but under different conditions, they can also be formed due to non-biological processes.
"What we have detected is what we would expect from a sample from an ancient lake environment on Earth", said Eigenbrode, of NASA's Goddard Space Flight Center.
Like the meteoric samples, the rocks sampled by Curiosity must be heated by the rover's instruments to very high temperatures, ranging between 500 and 800 degrees Celsius (932 and 1,472 degrees Fahrenheit), to have their organics released as gas.
The studies were conducted using evidence collected by NASA's Curiosity rover, which is now rolling around the Martian surface. Methane levels were measured over a period of 4.5 years, which showed an increase of methane during late winter in the southern hemisphere and late summer in the northern hemisphere.
In any case, however, the molecules may provide key information to scientists in their continuing search for life on Mars, since "All life that we know of is based on organic molecules", Eigenbrode explained. "But it gave us a lot of anticipation that, if we can find these molecules here, perhaps we're going to come across other layers of rock that have more organics in them". On Earth, 1,800 out of every billion molecules in the atmosphere is methane, and 95 percent of it comes for biological sources: Burning fossil fuels, decomposing debris, burping cows.
This is not the first time that Curiosity has detected organic molecules, but previous measurements were considered unreliable because of possible sample contamination and unwanted chemical reactions.
Updated on June 8 with news that Curiosity found the building blocks of life on Mars. "And it makes us more confident that if biomarkers" - or direct evidence of biologic activity - "are there, we might find them".
"We were kind of shocked to see that with the seasons, the signal changes by a factor of three, which is a huge change and completely unexpected", says Chris Webster, a rover scientist at NASA's Jet Propulsion Laboratory.