Superior tolerance to catalyst coking is obtained with a catalytic composite comprising a gallium component and a crystalline aluminosilicate incorporated with a phorphorus containing alumina. A five-fold reduction in the coke content of the spent catalyst of the instant invention is observed which is directly attributable to the phosphorus containing alumina. A novel method of preparing this catalyst is presented, along with a novel process for the dehydrocyclodimerization of C.sub.2 -C.sub.5 aliphatic hydrocarbons.