Batch experiments were conducted to investigate anoxic biodegradation of five refractory nitrogeneous heterocyclic compounds, i.e. pyridine, indole, quinoline, isoquinoline, 2-methyl quinoline, in coke plant wastewater. These compounds were effectively degraded by the denitrifiers in acclimated activated sludge within 60 h. The degradation rate was dependent upon chemical structures in the order: pyridine > indole > quinoline > 2-methyl quinoline > isoquinoline. Denitrification was a zero-order reaction, and the denitrification rate of individual compounds had a linear relationship with its corresponding molecular connectivity index.