A catalyst composition comprises a crystalline MCM-22 family molecular sieve and a binder, wherein the catalyst composition is characterized by an extra-molecular sieve porosity greater than or equal to 0.122 ml/g for pores having a pore diameter ranging from about 2 nm to about 8 nm, wherein the porosity is measured by N2 porosimetry. The catalyst composition may be used for the process of alkylation or transalkylation of an alkylatable aromatic compound with an alkylating agent. The molecular sieve may have a Constraint Index of less than 12, e.g., less than 2. Examples of molecular sieve useful for this disclosure are a MCM-22 family molecular sieve, zeolite Y, and zeolite Beta.