Crystals of 2-methyl-4-nitroaniline were grown from solution while subjected to a dc electric field of 9.8??10[exponent4] Vm???1. This resulted in an alteration of the unit cell lattice parameters while the space group was modified from Cc to one of its subgroups Pc. The modified crystals display an increased second harmonic generation efficiency accompanied by a decrease in the dielectric permittivity as well as changes in the internal and external vibrational modes.