Framework　materials　such　as　zeolites　and　mesoporous　silicas　are　commonly　used　for　many　applications,　especially　catalysis　and　separation.　Here　zeolite-mesoporous　silica　composite　catalysts　(employing　zeolite　Y,　ZSM-5,　KIT-6,　SBA-15　and　MCM-41　mesoporous　silica)　were　prepared　(with　different　weight　percent　of　zeolite　Y　and　ZSM-5)　and　assessed　for　catalytic　cracking　(using　n-heptane,　as　the　model　compound　at　550　degrees　C)　with　the　aim　to　improve　the　selectivity/yield　of　light　olefins　of　ethylene　and　propylene　from　n-heptane.　Physicochemical　properties　of　the　parent　zeolites　and　the　prepared　composites　were　characterized　comprehensively　using　several　techniques　including　X-ray　diffraction,　nitrogen　physisorption,　scanning　electron　microscopy,　fourier　transform　infrared　spectroscopy,　pulsed-field　gradient　nuclear　magnetic　resonance　and　thermogravimetric　analysis.　Catalytic　cracking　results　showed　that　the　ZY/ZSM-5/KIT-6　composite　(20:20:60　wt　%)　achieved　a　high　n-heptane　conversion　of　85%　with　approximately　6%　selectivity　to　ethylene/propylene.　In　contrast,　the　ZY/ZSM-5/SBA-15　composite　achieved　a　higher　conversion　of　95%　and　an　ethylene/propylene　ratio　of　8%,　indicating　a　more　efficient　process　in　terms　of　both　conversion　and　selectivity.　Magnetic　resonance　relaxation　analysis　of　the　ZY/ZSM-5/KIT-6　(20:20:60)　catalyst　confirmed　a　micro-mesoporous　environment　that　influences　n-heptane　diffusion　and　mass　transfer.　As　zeolite　Y　and　ZSM-5　have　micropores,　n-heptane　can　move　and　undergo　hydrogen　transfer　reactions,　whereas　KIT-6　has　mesopores　that　facilitate　n-heptane＇s　accessibility　to　the　active　sites　of　zeolite　Y　and　ZSM-5.