Creative people regulate their own attentional flexibility and focus in response to creative task demands in a way that favors the emergence of original and effective solutions. So far, not much is known about the neurobiological mechanisms that underlie such abilities. Here, the function of the locus coeruleus noradrenaline (LC-NA) system in creativity was explored using pupillometry. Two studies experimentally tested whether tonic pupil dilation (as a proxy for measuring tonic LC-NA activity) and phasic pupil dilation (as a proxy for measuring phasic LC-NA activity) predicted performance on divergent and convergent thinking using both psychometric (study 1) and real-world creativity tasks (study 2). During divergent thinking, it was consistently found that tonic pupil dilation predicted the generation of original ideas in both creativity tasks, and phasic pupil dilation predicted the generation of effective ideas only in the real-world creativity task. However, during convergent thinking, tonic and phasic pupil dilation did not predict creative task performance in both creativity tasks. Therefore, this study was the first to provide experimental evidence that suggests that tonic and phasic LC-NA activity differentially predict the generation of original and effective ideas during creative tasks that require divergent thinking.