Formation of N-2 during slow heating rate, temperature-programmed pyrolysis of a brown coal and a biodegraded leaf has been studied with a fixed-bed reactor in high-purity He. Formation profile of N-2 depends strongly on type of sample. Demineralization by acid washing drastically changes the formation profiles and decreases nitrogen conversion to N-2 for both the samples. Addition of iron to the demineralized brown coal promotes N-2 formation and restores the profile to that of its original one. On the other hand, addition of calcium catalyst onto the demineralized biodegraded leaf promotes N-2 formation and restores the profile to that of its raw sample. These results lead to the conclusion that inherent iron in the brown coal or inherent calcium in the biodegraded leaf is responsible for its remarkable formation of N-2, respectively.