The thermal hydrocracking of fluorene was investigated in the temperature range of 400 to 480 °C and hydrogen pressures of up to 375 atm. As main reaction products were found 2-methylbiphenyl, biphenyl, toluene and benzene. They account for about 90% of the converted fluorene. Only very low concentrations of diphenylmethane were detected at the highest temperature. This indicates that the opening of the phenyl - CH2 bond in fluorene is much faster than the splitting of the phenyl - phenyl bond. The splitting of the phenyl - phenyl bond in biphenyl, however, proceeded with a rate equal to the splitting of the phenyl - CH2 bond in fluorene and the phenyl - CH3 bond in 2-methylbiphenyl.