The magnetic field effects reported in 1973 for the thermal reaction of pentafluorobenzyl chloride with n-butyllithium in hexane were re-examined at 23 +/- 3 degreesC with modern techniques. Using a new reaction apparatus, which has an electromagnet (up to 14.9 kG) in a glove box under argon atmosphere (H2O and O-2 < 1 ppm), we studied the magnetic field effects on the yields of final products of pentafluorophenylpentane and decafluorodiphenylethane in the absence and presence of an external magnetic field of 14.9 kG. No significant magnetic field effect was observed upon the yields of pentafluorophenylpentane and decafluorodiphenylethane under well-controlled conditions with sufficient repetitions.