Here, we report the development of novel PET radiotracer ([¹¹C]CW22) of BET proteins. In vivo imaging results in rodents and nonhuman primates (NHP) demonstrate that [¹¹C]CW22 has excellent brain uptake, good specificity, good selectivity, suitable metabolism, appropriate kinetics and distribution in the brain. Our studies demonstrated that [¹¹C]CW22 exhibits ideal properties as a PET imaging probe of BET proteins for further validation.