The use of binary accelerator in sulphur vulcanisation has immense potential in various rubber industries. However, in some of the cases it was found that the secondary accelerator may have an adverse impact on human health due to it’s carcinogenic nature. In this study we report the influence of addition of a small amount of nitrile rubber on the curing activity of diene rubbers, for example polybutadiene rubber formulated with essential sulphur vulcanising ingredients. Nitrile rubber was used in a catalytic proportion and it’s effect was observed in both rate and state of sulphur vulcanisation. The vulcanisation reaction was found to be more spontaneous in presence of nitrile rubber which is confirmed by the lowering of activation energy obtained from vulcanisation kinetics. The improved state of vulcanisation refers to the alteration of network characteristics, like crosslinking density, as revealed by swelling studies and solid state NMR. The effect of network modification was also reflected by enhanced mechanical properties of the composites. FTIR studies indicate the formation of a new complex which arises due to the reactions between nitrile rubber and the existing ingredients like primary accelerator, sulphur and zinc oxide. This facilitates the vulcanisation reaction and thus an improved cure rate was obtained. Furthermore, a marginal improvement in thermal stability was found which was explained in terms of Ahagon plot. For the first time, nitrile rubber is used as a secondary accelerator or booster for sulphur vulcanisation and provides a way to replace conventional secondary accelerators.