Azido-hexynyl-pApG works as an initiator for mRNA translation and provides similar enhancement in stability and activity as capping reagents. The introduced azide function operates also as an reporter by modifiying the enzymatic capped mRNA via Click Chemistry either via SPAAC or by CuAAC. Since most RNAs are partially degraded by Cu(I) baseclick recommends labeling in copper free via SPAAC for example with our DBCO dyes.