1,3-Di-tert-butylhexahelicene1was synthesized in 95% yield by irradiation of 2-(3,5-di-tert-butylstyryl)-benzo[c]phenanthrene in hexane in the presence of iodine under anaerobic conditions. NMR-spectroscopy, X-ray analysis and force-field calculations give a consistent picture of the spatial structure of1in solution and in the solid phase. Partial resolution of the mixture of enantiomers was performed by chromatography over silicagel, coated with TAPA. The enantiomers of1are very resistant to racemization, which occurs only with a detectable rate at temperatures above 300°C. Racemization parameters reveal a high enthalpy and in contrast to other helicenes a positive entropy of activation. The mechanism of the racemization is discussed.