as a service to our authors and readers , this journal provides supporting information supplied by the authors . such materials are peer reviewed and may be reorganized for online delivery , but are not copyedited or typeset . technical support issues arising from supporting information ( other than missing files ) should be addressed to the authors .
abstractwe observe the diffusion anisotropy difference between singlet and triplet excitons in organic crystals ; that is , singlet and triplet excitons may have completely different spatial direction preference for diffusion . 
 this phenomenon can be ascribed to the distinct dependence of different excitonic couplings ( coulomb frster vs. exchange dexter ) existing in singlet and triplet excitons on their intermolecular distance and intermolecular orientation . 
 such a discovery provides insights for understanding the fundamental photophysical process in a vast range of organic condensedphase systems and optimizing the efficiency of organic optoelectronic materials .