Synthesized acyl phosphonates were studied for their selectivity towards mungbean and rice. Pre-plant and pre-emergence application of synthesized acyl phosphonates to mungbean and rice at concentrations 0, 100, 200, 300, 400 and 500 ppm showed that, in general, presence of diethyl moiety in the side chain of acyl phosphonates showed better herbicidal effect than the dibutyl group. Substitution of phenoxy ring by chloro and methyl group also enhanced the herbicidal activity. Application of phenoxy ring system having dibutyl group in the side chain gave increase in per cent seed germination, root and shoot length of mungbean at concentrations ranging from 100–400 ppm.
