a b s t r a c tA new microporous metal dicyanamide cluster, Co(hmt)(dca) 2 (hmt: hexamethylenetetramine, dca: dicyanamide), with accessible N-donor sites exhibits high CO 2 /N 2 selectivity, 83 at 295 K and 1 bar, for a mixture with a 15:85 CO 2 to N 2 ratio. Adsorption studies show that the use of hmt and dca moieties as building blocks for solid adsorbents can enhance the CO 2 :surface interactions due to N atoms available inside the pores, which is confirmed by X-ray single crystal studies.