Carboxylation of aromatics by CO₂ to generate corresponding carboxylic acids is recently providing a novel approach to utilize the green gas CO₂, in which the activation of CO₂ is the key procedure. Among the many catalytic systems employed in the carboxylation, the concept of “Frustrated Lewis Pairs” (FLPs) was scarcely mentioned, which perform excellently in activating small molecules like CO₂. The FLPs are combinations of Lewis acids and Lewis bases which failed to form adducts due to their bulky steric congestion. In this paper, we first attempted various Si/Al Based FLPs to catalyze the carboxylation of aromatics through the activation of CO₂, and a good yield of 62% - 97% was obtained. The reaction mechanism was proposed, involving the activation of CO2 mainly contributed by AlCl₃ in cooperation with organosilane, forming an intermediate consisting of CO₂, AlCl₃, and R₄Si, as well as the subsequent electrophilic attack to aromatics, thus to promote the carboxylation reaction.