This research article delves into the intriguing realm of intramolecular phenol-amide hydrogen bonds and their impact on the strength of amide NH groups. The study is rooted in the understanding that hydrogen bonding is a pivotal force in the structure and function of numerous biological systems, with the phenol-amide hydrogen bond being a common motif in proteins and other biomolecules. The research employs computational methods to model a series of secondary amides, each exhibiting varying degrees of phenol-amide hydrogen bonding. The strength of the amide NH groups is then evaluated based on their polarization, which is determined by the calculated atomic charges. The findings of the study reveal a clear correlation between the presence of a phenol-amide hydrogen bond and an increase in the polarization of the amide NH group. This increased polarization subsequently leads to a strengthening of the amide NH group. The results suggest that intramolecular phenol-amide hydrogen bonds can exert a significant cooperative effect on the strength of amide NH groups. This research not only provides valuable insights into the cooperative effects of hydrogen bonding in secondary amides but also paves the way for potential implications in the design of new biomolecules and the understanding of protein structure and function. The study underscores the importance of understanding the subtle interplays of molecular interactions in shaping the properties of biological systems.