The conditions of thermal isomerisation of nadic anhydride were optimised. Nadic anhydride (exo) and N-phenyl nadimide were polymerised metathetically using WCl6/(CH3)(4)Sn catalyst system. The effect of reaction parameters such as duration and monomer : tungsten : tin mole ratio on % conversion and intrinsic viscosity of the polymers was investigated. The polymers formed were characterised using H-1-NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA).