4-dimethyla-mino-N-methyl 4-stilbazolium tosylate（DAST） crystals were prepared by the slope nucleation method (SNM). The structural and optical properties of the grown crystals were studied by employing powder XRD and FIIR. The surface morphology of DAST crystals was observed by scanning electron microscope (SEM). The Vickers hardness studies were carried out on (001) and (110) faces of grown DAST crystal. The values of Meyer’s index number n and hardness were calculated from Hv. The results showed that the DAST crystals belong to the soft material category.