Thiophosphoryl disulfide was successfully used as a novel coupling agent to form a coherent blend comprising polar carboxylated nitrile rubber (XNBR) and nonpolar styrene-butadiene rubber (SBR) establishing close proximity between them through chemical bridging. The study reveals that XNBR in the presence of thiophosphoryl disulfide greatly improves the physical properties of SBR and thus acts as a reinforcing filler. It is noted that the physical properties of the vulcanizates obtained from the SBR-XNBR blend depend upon the SBR : XNBR ratio and the mode of cure. SEM studies corroborate the observed facts.