The apparatus and method of the present invention provides for conducting simultaneous multiple synthesis of general compounds, which often takes place under varied uneven conditions requiring heating, cooling, agitation, reagent/solvent additions to the reactor contents at each reaction vessel location, supply and maintenance of inert atmosphere and means to facilitate the reflux of the reactor contents. Thus, it becomes necessary to monitor and control the reaction conditions during the simultaneous multiple synthesis of general compounds. The apparatus allows the user to connect various independently controlling and conveying means to each reaction vessel through multiple ports provided on a stopper mounted on each reaction vessel. The apparatus of the present invention permits user to readily access the reaction vessels without interrupting the reactions occurring in the adjacent reaction vessels. The unique geometry and shape of the stopper allows positioning of multiple ports, while still providing the stopper with a compact size. As a result, a large array of reaction vessels can be accommodated in the device of the present invention without significantly increasing the overall size of the apparatus. Some of the general compounds that can be readily synthesized by the apparatus and the method of the present invention include inorganic compounds as well as organic compounds, such as oligomers, polymers, agricultural chemicals, drugs, peptides and oligonucleotides.