It was difficult to determine the IQ ranking of the characters in Detective Conan because each character had their own unique abilities and background. However, based on the plot and character performance, here are some of the characters that might be considered the smartest: Kudo Shinichi: As Conan's father, he is an excellent detective and scientist with excellent reasoning ability and wisdom. 2 Maori Kogoro: Although he is not very good at reasoning, his wit and calmness can often help Conan solve problems. 3. Concubine Yingli: She is a smart lawyer who is good at law and reasoning. 4. Yuanshan and Ye: She is an excellent police officer and detective with excellent reasoning ability and logical thinking. 5 Akai Shuichi: He is a mysterious detective with excellent intelligence and reasoning skills. He is also the natural enemy of Conan's father. It should be noted that IQ is only a part of a person's ability. Other factors such as experience, background, emotions, etc. will also affect the character's performance and ranking.