A new sulfonic acid containing ionic-liquid-based periodic mesoporous organosilica (PMO-IL-SO3H) material was prepared and its catalytic application was investigated in the esterification of carboxylic acids with alcohols. The PMO-IL-SO3H nanocatalyst was first characterized with diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and nitrogen sorption analysis. Then, the catalytic performance of this material was studied in the esterification of carboxylic acids with short- and long-chain aliphatic alcohols, cyclic alcohols, and benzylic alcohols under solvent-free conditions. The results showed that the catalyst has superior activity for the conversion of several alcohols to afford the corresponding ester products in excellent yields and high purity. Moreover, the catalyst could be recovered and reused several times without a significant decrease in activity and product selectivity.