Light hydrocarbon separation is a crucial process associated with high energy expenditure in the petrochemical industry. The utilization of porous organic materials as solid porous adsorbents for light hydrocarbon separation has found widespread attention because of the advantages of low cost, excellent stability, and good recyclability. Here, we present the facile synthesis of a porous organic material, constructed from pyridine-triphenylborane by using a Friedel-Crafts alkylation coupling reaction, affording the hyper-cross-linked polymer, HCP-B. HCP-B features significant thermal stability, and high surface area. Gas adsorption experiments show that this material adsorbs much larger amounts of ethane, ethylene, and acetylene than that of methane. Ideal adsorbed solution theory (IAST) calculations also predict that HCP-B selectively adsorbs ethane, ethylene, and acetylene over methane. Both are indicative of the great potential of HCP-B in light hydrocarbon separation.