Mobile optical communications has so far largely been limited to short ranges of about ten meters, since the highly di- rectional nature of optical transmissions would require costly mechanical steering mechanisms. Advances in CCD and CMOS imaging technology along with the advent of visible and infrared (IR) light sources such as (light emitting diode) LED arrays presents an exciting and challenging concept which we call as visual-MIMO (multiple-input multiple- output) where optical transmissions by multiple transmitter elements are received by an array of photodiode elements (e.g. pixels in a camera). Visual-MIMO opens a new vista of research challenges in PHY, MAC and Network layer research and this paper brings together the networking, communications and computer vision fields to discuss the feasibility of this as well as the underlying opportunities and challenges. Example applications range from household/factory robotic to tactical to vehicular networks as well pervasive computing, where RF communications can be interference- limited and prone to eavesdropping and security lapses while the less observable nature of highly directional optical transmissions can be beneficial. The impact of the characteristics of such technologies on the medium access and network layers has so far received little consideration. Example characteristics are a strong reliance on computer vision algorithms for tracking, a form of interference cancellation that allows successfully receiving packets from multiple transmitters simultaneously, and the absence of fast fading but a high susceptibility to outages due to line-of-sight interruptions. These characteristics lead to significant challenges and opportunities for mobile networking research.