An interior mirror system suitable for use in a vehicle comprises an interior rearview mirror assembly having a mirror support assembly adapted for attachment to an interior portion of the vehicle. The interior rearview mirror assembly further comprises an imaging sensor. An electrochromic reflective mirror element is disposed in a housing with its the rearward field of view pivotally adjustable about the mirror support assembly via a pivot element when the interior rearview mirror assembly is attached by the mirror support assembly at an interior portion of the vehicle. Electronic circuitry that includes a compass sensor is disposed within the housing to the rear of the reflective mirror element and the electronic circuitry includes a microprocessor that at least partially controls automatic dimming of the reflectivity of the reflective mirror element in response to glare conditions detected by at least one photo sensor. The microprocessor also at least partially establishes a heading of the vehicle in response to input from said compass sensor and the microprocessor at least partially controls a headlight of the vehicle in response to detection of at least one of an oncoming headlight of another vehicle and a taillight of another vehicle by the imaging sensor.