Before scaling up to production, it is of high importance to evaluate the potential of a reaction to lead to an undesired thermal degradation event. The use of a large amount of compounds is usually required for a reliable calorimetry study. In this work, we report the development of a milliliter-scale reaction calorimeter for reaction screening applications. The setup was designed using laboratory equipment and characterized and validated with routine experiments. The results were sufficiently accurate enabling us to observe trends in the measured reaction enthalpies of a family of compounds reacting with strong bases as a function of the compounds' structures.. The use of the microscale tailor-made calorimeter is considered very valuable for potentially highly energetic reactions since reaction calorimetry studies can be performed accurately and safely with small amounts of valuable materials.