AbstractInter‐molecular association in the chloroform‐acetone and diethyl ether‐chloroform systems was studied in terms of polarization at optical frequency, of which the theory had been developed in the previous paper.In the chloroform‐acetone system, the association ratio of acetone to chloroform was found to be 1:1 and 1:2 corresponding to the formation of the intermolecular associaton complexes AB and AB2where A stands for acetone and B for chloroform.While in the case of the diethyl ether‐chloroform system, only complex of 1:1 association ratio was detected.The polarizability constants and collision radii of these association complexes were determined exper