Abstract: An ex situ selectivated catalytic molecular sieve for enhanced shape selective hydrocarbon conversions in which a catalytic molecular sieve is modified by being exposed to at least two selectivation sequences, each sequence including an impregnation of the molecular sieve with a selectivating agent and a subsequent calcination of the impregnated molecular sieve. The ex situ selectivation method is also described, including the use of low volatility organic carriers for the selectivating agent. Also, a method for moderate steaming of the ex situ selectivated molecular sieve. Also a method for in situ trim-selectivating the ex situ selectivated catalytic molecular sieve. Also described is the process for shape selective hydrocarbon conversion comprising contacting a hydrocarbon feedstream under conversion conditions with the modified catalytic molecular sieve.