We report in this letter the measurement of the hyperpolarizabilities of a series of donor-substituted triaryl-1,3,5-triazinanes-2,4,6-triones by hyper Rayleigh scattering (HRS). A remarkable transparency–nonlinearity trade-off is evidenced for these octupolar NLO-phores which might be accessed in a straightforward synthetic way and in a few steps from commercial isocyanates.