This review article by Hua Bai and Gaoquan Shi from Tsinghua University, China, provides a comprehensive overview of gas sensors based on conducting polymers such as polyaniline (PAni), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene) (PEDOT). The authors discuss the sensing mechanisms and configurations of these sensors, highlighting their advantages over traditional metal oxide sensors, including high sensitivity, short response times, and ease of synthesis. The review also addresses the factors affecting the performance of these sensors, such as doping levels, chemical interactions with analytes, and mechanical properties. Additionally, the article discusses the disadvantages of conducting polymer sensors and provides a brief outlook on future research directions in this field. The sensing principles of different sensor configurations, including chemiresistors, transistors, diodes, optical devices, and piezoelectric crystal sensors, are detailed, along with their advantages and limitations.This review article by Hua Bai and Gaoquan Shi from Tsinghua University, China, provides a comprehensive overview of gas sensors based on conducting polymers such as polyaniline (PAni), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene) (PEDOT). The authors discuss the sensing mechanisms and configurations of these sensors, highlighting their advantages over traditional metal oxide sensors, including high sensitivity, short response times, and ease of synthesis. The review also addresses the factors affecting the performance of these sensors, such as doping levels, chemical interactions with analytes, and mechanical properties. Additionally, the article discusses the disadvantages of conducting polymer sensors and provides a brief outlook on future research directions in this field. The sensing principles of different sensor configurations, including chemiresistors, transistors, diodes, optical devices, and piezoelectric crystal sensors, are detailed, along with their advantages and limitations.