The selective catalytic reduction of nitric oxide using copper ion-exchanged SSZ-39 is described. Samples made from identical synthesis gels with only different amounts of the trans isomer of the SDA exhibit both different copper metal uptake during exchange as well as different catalytic activity. The reactivity differences are most pronounced at low (<250 degrees C) and high temperatures, with conversions at 200 degrees C varying by nearly twenty percentage points (70 versus 90%). Samples with nearly identical Si/Al and Cu/Al values were prepared and show different catalytic activities under the conditions investigated. SEM and nitrogen physisorption suggest that this is not primarily a result of different particle sizes or micropore volumes. Preliminary analyses using EDS in conjunction with TEM indicate on the length scale of tens of nanometers aluminum zoning features appear as amount of the trans SDA used in the synthesis gel changes. These results indicate one route to manipulating local structure in zeolites that impact both the number of active sites as well as reactivity. (C) 2020 Elsevier Inc. All rights reserved.