Preparation of trifluoromethylsulfenyl pyrazole involves a) halogenating aromatic compound to obtain polyhalogenated perhaloalkyl benzene; b) reacting in a polar solvent to give halo-perhaloalkyl aniline; c) reacting halo-perhaloalkylaniline compound with halogenating agent; d) isolating polyhalogenated perhaloalkylaniline compound; e) diazotizing isolated polyhalogenated aniline; f) reacting diazotized derivative with cyanoalkyl propionate derivative; g) isolating pyrazole compound; h) sulfinylating crude pyrazole compound; and i) oxidizing isolated thio pyrazole compound. Preparation of trifluoromethylsulfenyl pyrazole compound of formula (I) involves a) halogenating an aromatic compound of formula (II) to obtain polyhalogenated perhaloalkyl benzene compound of formula (III); b) reacting, in a polar solvent selected from N-methyl pyrrolidone, dimethyl sulfone, N,N-dimethylimidazolidinone and diphenyl sulfone, the compound of formula (III) with anhydrous ammonia in the presence of an alkali halide (preferably potassium fluoride) at 200-300[deg] C (preferably 235-250[deg] C), and a pressure of 20-50 (preferably 25-42) kg/cm 2>;, to obtain a halo-perhaloalkyl aniline compound of formula (IV); c) reacting halo-perhaloalkylaniline compound (IV) with a halogenating agent selected from chlorine, sulfurylchloride, thionyl chloride and phosphorus pentachloride (preferably sulfurylchloride) in a solvent (preferably a chlorinated solvent selected from carbon tetrachloride, dichloromethane, chlorobenzene and o-dichlorobenzene), to obtain a product mixture containing polyhalogenated perhaloalkylaniline compound of formula (V); d) isolating polyhalogenated perhaloalkylaniline compound (V) preferably by distillation, from the product mixture; e) diazotizing isolated polyhalogenated aniline (V) with nitrosyl sulfuric acid in the presence of an acid solvent to form diazotized derivative of compound (V); f) reacting diazotized derivative with cyanoalkyl propionate derivative (pre