The Kerr response of seven nematic substances has been measured just above their nematic‐isotropic transition temperature, in their isotropic state. If the reciprocal of the Kerr constantBis plotted against temperature, a linear relationship analogous to the Curie‐Weiss dielectric relationship in ferroelectrics is found in all cases. The transient Kerr response—that is, the variation of induced birefringence with time in response to a field step—was also measured in three of the compounds. Inp‐(p‐ethoxybenzylidene) amino benzonitrile (EBAB), a maximum Kerr constant of 175×10−10cm2V−1was observed, together with a response time of 13 nsec. The extremely short response time indicates that molecular association does not take place. On the other hand,n‐(p‐methoxybenzylidene)‐p‐butylaniline (MBBA) under similar conditions showed a response time of 3 &mgr;sec, indicating that a high degree of association does take place in the isotropic phase.