A tiled flat panel lighting system includes flat panel light emitting units, each unit comprising a light emitting region and at least two pairs of first and second electrical contacts which are accessible external to the unit, wherein the first electrical contacts of the pairs are electrically connected within the unit, the second electrical contacts of the pairs are electrically connected within the unit, the light emitting region is electrically connected to the connected first contacts and to the connected second contacts. A plurality of units may be electrically interconnected through pairs of the externally accessible first and second electrical contacts positioned at one or more adjacent edges of each of the units. In a further embodiment, a tiled flat panel lighting system comprising a plurality of flat panel light emitting units, wherein at least two of the flat panel light emitting units contain controllers, where the plurality of units are interconnected through contacts positioned at one or more adjacent edges of each of the units, wherein the interconnections provide for communications signals between the controllers.