Environmentally benign adsorption heat pump (AHP) and desalination (AD) systems have already attracted considerable attention for space cooling/heating and potable water production since they require no electricity and are driven by solar or waste heat. The adsorbent material is the key element of these adsorption systems. Highly porous carbon-based consolidated composites are very promising adsorbents. Specific heat capacity (cp) of adsorbent is one of the most significant thermophysical properties. It plays a vital role in predicting the performance of the systems accurately. However, the estimation of the cp of adsorbent materials is a demanding issue and has not been focused sufficiently yet. Therefore, this chapter will present the significance of specific heat capacity, detailed experimental procedure, and the cp of composites, as well as the parent materials at the operating temperature range of AHP and AD systems. Finally, all the experimental data are analyzed rigorously and correlated with the established equations of cp. The presented experimental cp data along with the fitted parameters are crucial in the design of AHP and AD systems.