Constructing metalated three-dimensional (3D) covalent organic frameworks is a challenging synthetic task. Herein, we report the synthesis and characterization of a highly porous (SA(BET) = 5083 m(2) g(-1)) 3D COF with a record low density (0.13 g cm(-3)) containing, pi-electron conjugated dehydrobenzoannulene (DBA) units. Metalation of DBA-3D-COF 1 with Ni to produce Ni-DBA-3D-COF results in a minimal reduction in the surface area (SA(BET) = 4763 m(2) g(-1)) of the material due to the incorporation of the metal within the cavity of the DBA units, and retention of crystallinity. Both 3D DBA-COFs also display great uptake capacities for ethane and ethylene gas.