Reduction of a series of N,N’-diaryl adipyl bis-azo compounds using hydrazine hydrate as reductant was investigated. The products were characterized by elemental analysis, IR and 1H NMR methods and confirmed to be N,N’-diaryl adipyl dihydrazine. The results show that hydrazine hydrate can selectively reduce azo bonds with other potential reducible bonds intact in the N,N’-diaryl adipyl bis-azo compounds. The yields are high up to 92% under mild reaction conditions. According to the previous reports, this reduction process was attributed to an indirect reduction mechanism through an intermediate diimide. Reduction of a series of N, N’-diaryl adipyl bis-azo compounds using hydrazine hydrate as reductant was investigated. The products were characterized by elemental analysis, IR and 1H NMR methods and confirmed to be N, N’-diaryl adipyl dihydrazine. The results show that hydrazine hydrate can reduce reduce azo bonds with other potential reducible bonds intact in the N, N’-diaryl adipyl bis-azo compounds. According to the previous reports, this reduction process was attributed to an indirect reduction mechanism through an intermediate diimide.