In this communication, we report an azine linked covalent organic framework based on a six-fold symmetric hexphenylbenzene (HEX) monomer functionalized with aldehyde groups. HEX-COF 1 has an average pore size of 1 nm, a surface area in excess of 1200 m(2) g(-1) and shows excellent sorption capability for carbon dioxide (20 wt%) and methane (2.3 wt%) at 273 K and 1 atm.