Catalytic reduction of a mixture of 3- and 4-trimethylsilyl-1-nitrobenzene over palladium-carbon catalyst, hydrolysis with dil. hydrochloric acid, and fractional distillation of the hydrolysate afford 3-trimethylsilylaniline in a good yield. Bromination of 3-trimethylsilylacetanilide (II) gives the 4-bromo compound (III), whose further bromination affords 3, 4-dibromoacetanilide. Nitration of (II) affords 2-nitro-5-trimethylsilylacetanilide (IV), whose catalytic reduction over palladium-carbon gives 2-amino-5-trimethylsilylacetanilide (V). (V) is easily hydrolyzed by dil. hydrochloric acid to form 2-methylbenzimidazole. Bromination of 4-trimethylsilyl-1, 2-phenylenediamine diacetate gives 4-bromo compound. These experiments have revealed that the introduction of o, p-orienting groups in the position ortho or para to the acetamide group in (II) weakens the bond between silicon and aromatic ring due to over-lapping of the +T effect of the group introduced and +I effect of the trimethylsilyl group, and that the second substitution occurs at the ring-carbon to which the trimethylsilyl group is bonded.