We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary ( or triple ) L dwarf 2MASS J0850359+105716 .
This nearby ( \sim 31 pc ) , widely separated ( \sim 7700 AU ) quadruple system was identified through a cross-match of proper motion catalogs .
Follow-up imaging and spectroscopy of NLTT 20346 revealed it to be a magnetically active M5+M6 binary with components separated by \sim 2 \arcsec ( 50-80 AU ) .
Optical spectroscopy of the components show only moderate H \alpha emission corresponding to a statistical age of \sim 5 - 7 Gyr for both M dwarfs .
However NLTT 20346 is associated with the XMM-Newton source J085018.9+105644 , and based on X-ray activity the age of NLTT 20346 is between 250-450 Myr .
Strong Li absorption in the optical spectrum of 2MASS J0850+1057 indicates an upper age limit of 0.8 - 1.5 Gyr favoring the younger age for the primary .
Using evolutionary models in combination with an adopted system age of 0.25-1.5 Gyr indicates a total mass for 2MASS J0850+1057 of 0.07 \pm 0.02 M _ { \sun } if it is a binary .
NLTT 20346/2MASS J0850+1057 joins a growing list of hierarchical systems containing brown dwarf binaries and is among the lowest binding energy associations found in the field .
Formation simulations via gravitational fragmentation of massive extended disks have successfully produced a specific analog to this system .