NOVELTY - Preparation of a substituted nitro-benzene compound (I), comprises: (a) contacting in a reaction mixture a substrate compound comprising substituted benzene compound (II) with polyphosphoric acid in the presence of a catalytic material; and (b) adding nitric acid to the reaction mixture to provide a molar ratio of nitric acid to substrate compound (on a 100% nitric acid basis) 1/1-1/1.5, and a weight ratio of nitric acid to polyphosphoric acid of 15/85-40/60, to form (I).    USE - The process is useful for preparing substituted nitro-benzene compound (claimed) including nitrotoluenes, nitroxylenes, nitrochlorobenzenes and other nitroaromatics, which is useful as an intermediates in the synthesis of a variety of industrial materials including aromatic diamines, explosives, dyes, pharmaceuticals, perfumes, pesticides, herbicides (such as pre-emergent herbicides), fiber systems and many specialty chemicals.    ADVANTAGE - The process is environmentally friendly and commercially viable, and provides high conversion for the selective nitration of aromatic compound.    DETAILED DESCRIPTION - Preparation of a substituted nitro-benzene compound of formula (I), comprises: (a) contacting in a reaction mixture a substrate compound comprising substituted benzene compound of formula (II) with polyphosphoric acid in the presence of a catalytic material comprising a large pore, acidic zeolite having a molar ratio of silicon/aluminum of greater than or equal to 5, or a large pore, hydrophobic molecular sieve having a silicon content great than 35 wt.%, where the ratio of the weight of the catalytic material to the weight of the substrate compound is 1/99-25/75; and (b) adding nitric acid to the reaction mixture to provide a molar ratio of nitric acid to substrate compound (on a 100% nitric acid basis) of 1/1-1/1.5, and a weight ratio of nitric acid to polyphosphoric acid of 15/85-40/60, to form (I).    X = 1-20C hydrocarbyl, preferably CH3 (optionally substituted with halo, preferably F), halo, carboxylic acid or nitrile.