Luminescent solar concentrators are translucent photovoltaic modules potentially used for building window. To store the energy generated by them, a separate energy storage module and voltage regulator module are required, but it is clear that this pairing is unwieldy for application. To address this problem, we propose a "face-to-face" tandem integration of luminescent solar concentrators and electrochromic supercapacitors. In this case, the separated energy storage module and voltage regulator module are not required, since the electric energy produced by concentrators under sunlight can be directly stored by the supercapacitors with matched voltage window. The charged energy storage module can be used to supply low-power devices. Moreover, electrochromic supercapacitors exhibit adjustable average visible transmission under different energy storage state, making the integrated device interesting for self-powered electrochromic smart windows or display devices. As an example, a self-powered information instruction display is prepared, and text messages could be clearly and rapidly displayed in a controllable manner. The integrated device capable of photovoltaic conversion, energy storage, and electrochromism is a promising alternative for smart windows.