It is not known when Li Cou was born — but as his youngest known older brother, Li Han, was born in 809, and his eldest known younger brotherLi Rong was born in 812, he must have been born between these points. He was the sixth son of Emperor Muzong, although the identity of his mother had been lost to history. He was said to be mild in temperament and appropriate in his behavior in his youth. In 821, when Emperor Muzong created his sons, as well as a number of younger brothers who had not been created titles, imperial princes, Li Cou was created the Prince of Zhang.
By 831, an older brother of Li Cou's, Emperor Wenzong, was emperor. Emperor Wenzong, apprehensive of how much control the powerful eunuchs had on his government at the time, had been planning with the chancellor Song Shenxi a way to eliminate the powerful eunuchs. As part of the plan, Song recommended Wang Fan to be the mayor of Jingzhao Municipality and informed him of the plan. Wang Fan, instead, leaked the plan, and the powerful eunuchWang Shoucheng and Wang Shoucheng's strategist Zheng Zhu came to know about the plan. Zheng reacted by ordering the Shence Army officer Doulu Zhu to falsely accuse Song of plotting treason to put Li Cou on the throne. When Wang Shoucheng relayed the accusation to Emperor Wenzong, Emperor Wenzong believed it and was angry. Wang Shoucheng initially wanted to take this opportunity to massacre Song's household, but was stopped by another powerful eunuch, Ma Cunliang. However, during the subsequent investigations by Shence Army officers, after an attendant official to the imperial princes, Yan Jingze, and Song's associate Wang Shiwen were tortured and confessed to serving as conduits for messages between Song and Li Cou, Song was found to be guilty and was set to be executed. The advisorial officials Cui Xuanliang, Li Guyan, Wang Zhi, Lu Jun, Shu Yuanbao, Jiang Xi, Pei Xiu, and Wei Wen urged caution, however, believed there were substantial questions in the matter and urged a reinvestigation by imperial government officials. The chancellor Niu Sengru also took the same view. Zheng, fearing that a reinvestigation would lead to discovery of the truth, suggested to Wang Shoucheng that he recommend to Emperor Wenzong that neither Song nor Li Cou be executed. Li Cou was thus demoted to the title of Duke of Chao County while Song was demoted to be the military advisor to the prefect of Kai Prefecture.
Aftermaths
In 835, Li Cou died, and was posthumously created the Prince of Qi. In 836, after Emperor Wenzong came to believe that Song Shenxi was innocent of wrongdoing, he ordered Song's posthumous rehabilitation. In 838, he further ordered that Li Cou be posthumously honored Crown Prince Huaiyi.
