The benign synthesis of a macroporous polystyrene (MPS) supported chromium MPS-Cr(III)-alen catalyst has been carried out precisely and characterized using different spectroscopic techniques such as Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The MPS-Cr(III)-alen catalyst shows noteworthy performance for the sustainable production of cyclic carbonates from various substituted epoxides employing a CO₂ balloon at room temperature under solvent free conditions. Additionally, the MPS-Cr(III)-alen material was also evaluated for the selective oxidation reaction of aromatic alkenes in the presence of 30% aqueous H₂O₂. This material can be easily reused for several runs with almost consistent efficiency.