Large single crystals of 5,5 '-distyryl-2,2 '-bithiophene (DS-2T) were grown from tetrahydrofurane (THF) solution, and the crystal structure was analyzed by x-ray diffractometry. In-situ observation of crystal growth in solution was performed, and a unique change in the crystal habit depending on growth conditions is found. The change in crystal habit from a truncated parallelogram shape to a slender hexagonal shape with re-entrant angles at the both side can be explained as the consequence of kinetic roughing and Berg effect.