HQNO is primarily used in biochemical research to study electron transport chains, particularly in mitochondria and bacteria. It acts as an inhibitor of quinol oxidase, effectively blocking the transfer of electrons in the respiratory chain. This property makes it a valuable tool for investigating cellular respiration and energy production processes. Additionally, HQNO is utilized in studies focusing on bacterial biofilms and antibiotic resistance, as it can disrupt microbial metabolism and growth. Its role in these areas aids in understanding microbial behavior and developing strategies to combat resistant strains.