An inquiry-based learning approach was implemented into comprehensive organic chemistry experiments focusing on the formation process of N-phenylbenzamide from the reaction between N-benzylideneaniline and benzoyl peroxide in commercial dimethyl sulfoxide. Students conducted comparative experiments using alternative reagents or reaction conditions to produce products. After structure determination of the products by NMR and GC--MS, the observed structural difference can lead to the conclusion that the C-N double bond cleavage from N-benzylideneaniline releases aniline, which then reacts with benzoyl peroxide to form the product N-phenylbenzamide. This comprehensive experiment provides a heuristic inquiry-based training for upper-division chemistry undergraduate students to gain experimental skills, analyze data, interpret spectra, and elucidate the amide formation process.