In present work, we fabricate large area, all flexible and microwaveable PDMS microfluidic reactor that is printed via 3D bioplotter system. The sacrificial microchannels are printed on Polydimethoxylane (PDMS) substrates by direct ink writing method using water soluble Pluronic F-127 ink and encapsulated between PDMS layers. The structure of micrometer sized channels is analyzed by optical and electron microscopy techniques. The fabricated flexible microfluidic reactors are utilized for acetylation of different amines under microwave irradiation to get acetylamides in shorter reaction time and good yields in Microwave Assisted Flow Organic Synthesis (MAFOS).