Density functional theory (DFT) has been widely recognized to be the most prevalent computational method in the past decades because it is both accurate and efficient for modeling the electronic structure of molecules and solids alike. However, most people are unaware that DFT also provides the conceptual framework to appreciate stability, bonding, reactivity, and other physiochemical properties. In this Perspective, focusing on this conceptual subject of DFT, we outline the four currently available density-based frameworks, illustrate several recent advances of applying these frameworks to understand chemical concepts and properties, and then provide outlooks for a few possible future developments.