Four isostructural pillared-layer metal-organic frameworks (as 1-ims series) are successfully synthesized via the charge-balance approach, where trigonal [Zn-2(CO2)(3)] cluster-based cationic layers [Zn-2(NH2-BTB)](+) (NH2-H3BTB = 1,3,5-(3-benzoic acid) aniline) are connected by a series of 2-substituted imidazolates. The 1-ims supply a systematic platform to explore the adsorption of light hydrocarbons. Especially, 1-ims shows good adsorption selectivity of C-3/C-1 and C-2/C-1, and the selectivities of C3H8/CH4 are all over 100 at room temperature. These results demonstrate that introduction of functional group plays a key role on tuning the channel and pore size as well as improving the adsorption selectivity.