L-DNA, the mirror image of natural DNA forms structures of opposite chirality. We demonstrate here that a short guanine rich L-DNA strand forms a tetramolecular quadruplex with the same properties as a D-DNA strand of identical sequence, besides an inverted circular dichroism spectra. L- and D-strands self exclude when mixed together, showing that the controlled parallel self-assembly of different G-rich strands can be obtained through L-DNA use.