An electronic device has an electrically adjustable shutter. The shutter may be placed in a transparent state or a nontransparent state. The shutter may overlap a portion of a display, may overlap a liquid contact indictor or a structure with text in a device, or may overlap an optical component such as an optical proximity sensor, ambient light sensor, visible light-emitting diode or laser, infrared light-emitting diode or laser, visible light image sensor, or infrared light image sensor. Control circuitry in the electronic device may place the shutter in an opaque state to hide an overlapped component from view or may place the shutter in a transparent state to allow the overlapped component to transmit or receive light. The adjustable shutter may exhibit changes in its transmission spectrum in different modes of operation and may be used as a camera filter or neutral density filter.