This work synthesized a new series of pyrazoline compounds containing azo linkages via classical and one-pot three-component reactions. The progress started with 3-chloro,4-methyl aniline, which has been diazotized and coupled with 4-hydroxy acetophenone to form azo compound 1-(3-((3-chloro-4-methyl phenyl) diazenyl)-4-hydroxyphenyl) ethan-1-one (1) and converted to 1-(4-(benzyloxy)-3-((3-chloro-4-methyl phenyl) diazenyl) phenyl) ethan-1-one (2). The later azo compound was subjected to both classical and one-pot methods to give target pyrazoline derivatives. The structure of all newly obtained compounds was supported by spectral data ( 1 H-NMR, 13 CNMR, Dept.135, and FT-IR). Finally, some pyrazoline derivatives were estimated for their antibacterial activity against Escherichia coli as gram-negative and Staphylococcus aureus as grampositive. The results showed significant activity against both types of bacteria.