Imagination is an important human capability which inspires individuals to engage in creative thinking and performance. Two studies were combined to examine the imaginative capability and to test an instrument regarding this capability by using the Rasch modeling analysis. The results indicated that imaginative capabilities consisted of three components, namely initiating imagination, conceiving imagination, and transforming imagination. "Initiating imagination" consisted of three characteristics: exploration, novelty, and productivity. "Conceiving imagination" consisted of five characteristics: effectiveness, dialectics, sensibility, intuition, and concentration. "Transforming imagination" consisted of two characteristics: crystallization and transformation. The current study provided intriguing insights into the characteristics and categories of human imagination. The imaginative capability scale was developed to be both empirically valid and easy to administer in diverse domains. The results seem productive enough to warrant further inquires and to be used in both teachers’ instructional evaluation and students’ self assessment.