The invention relates to crystalline forms of (S)-(2-(6-chloro-7-methyl-1H-benzo[d]imidazol-2-yl)-2-methylpyrrolidin-1-yl)(5-methoxy-2-(2H-1,2,3-triazol-2-yl)phenyl)methanone, processes for the preparation thereof, pharmaceutical compositions containing such crystalline forms, pharmaceutical compositions prepared from such crystalline forms, and their use as a medicament, especially as orexin receptor antagonists.本發明係關於(S)-(2-(6-氯-7-甲基-1H-苯并[d]咪唑-2-基)-2-甲基吡咯啶-1-基)(5-甲氧基-2-(2H-1,2,3-三唑-2-基)苯基)甲酮之晶形、其製備方法、含有該等晶形之醫藥組合物、自該等晶形製備之醫藥組合物,及其作為藥劑、尤其作為食慾素受體拮抗劑之用途。