NOVELTY - Preparing methyl 5-(phenylthio)-1H-benzo(d)imidazole-2-ylcarbamate (V) involves coupling 5-chloro-2-nitroaniline (I) with thiophenol (II) in presence of organic solvent, phase transfer catalyst and aqueous base to obtain 2-nitro-5-(phenylthio)aniline (III); reduction of organic layer containing compound (III) to obtain 4-(phenylthio)benzene-1,2-diamine (IV); adding water and mineral acid to organic layer of the compound (IV); and treating obtained mineral acid salt of compound (IV) in aqueous layer with methyl cyano carbamate or its salt in presence of ketone solvent.    USE - For preparing methyl 5-(phenylthio)-1H-benzo(d)imidazole-2-ylcarbamate (claimed) useful as anthelmintic against gastrointestinal parasites including giardia, roundworms, hookworms, whipworms, the taenia species of tapeworms, pinworms, aelurostrongylus, paragonimiasis, strongyles and strongyloides for treating helminth infestations which are conditions of major importance causing serious health problems, including mortality in domestic animals, such as cattle, sheep, pigs, goats, dogs and poultry; and also in horses, fish, cats, rabbits and seals.    ADVANTAGE - The present method is simple, safe, ecofriendly and cost effective. The method provides the product with good yield and superior purity. The same organic solvent is used for coupling, reduction and salt formation; and is recovered and stored for reuse. The process supports green chemistry approach by using same solvents in process which further recovered and preventing pollution at its source. No alkaline or acidic waste is generated in last step and the aqueous effluent of the step has neutral pH.    DETAILED DESCRIPTION - Preparing methyl 5-(phenylthio)-1H-benzo(d)imidazole-2-ylcarbamate (V) involves: a) coupling 5-chloro-2-nitroaniline (I) with thiophenol (II) in presence of organic solvent, phase transfer catalyst and aqueous base to obtain 2-nitro-5-(phenylthio)aniline (III); b) subjecting the organic layer from step (a) containing the compound (III) to reduction using aluminum oxide, EDTA, iron or acid salt of iron and hydrazine hydrate to obtain 4-(phenylthio)benzene-1,2-diamine (IV); c) adding water and mineral acid to the organic layer from step (b) containing compound (IV), followed by stirring and allowing layer separation to get mineral acid salt (IV) in aqueous layer; and d) treating mineral acid salt (IV) in aqueous layer with methyl cyano carbamate or its salt in presence of ketone solvent.