Trisubstituted pyrimidines were synthesised using 2% butanediol dimethacrylate cross linked chloromethyl polystyrene. The polymer was reacted with guanidine and the resulted guanidine functionalised resin was treated with 2-(1-ethoxyethylidene)malononitrile form a polymer bound 2,4-diaminopyrimidine-5-carbonitrile. The pyrimidine nucleus was then detached from the resin using TFA cleavage. The product was isolated with good yield. The reaction was also carried out under microwave reaction conditions and yield was found to be considerably enhanced with significant decrease in the total reaction time. The guanidine functionalised resin was treated with ethylcyano actate/malononitrile to afford 4,6-diamino pyrimidinone and 2,4,6-triaminopyrimidine derivatives. The products were characterized by IR, NMR and HRMS analysis.