The second-order nonlinear susceptibility of some novel 7,7-diarylnorbornane compounds in chloroform solution has been measured by EFISH at a fundamental wavelength lambda = 1064 nm. Values of beta(z) for the cofacial apical molecules (1-6) are enhanced in comparison tp:those reported for the uncoupled aryl rings. Highest value, beta(z)(1064 nm) = 21 x 10(-30) esu, similar to that reported for the linearly conjugated p-nitroaniline molecule, was measured for the amino (donor) and nitro (acceptor) Substituted compound 6. This result emphasizes the role of homoconjugative interactions, promoted:by exchange coupling through the ipso (apical) C atoms, on interannular charge-transfer and nonlinear optical response. On the other hand, the propeller compound 7, where the aryl rings are twisted, does show only a small enhancement in comparison to the predictions of an additive model.