Short, dye‐labeled oligonucleotides have been used as primers in template‐controlled polymerization reactions of RNA. The synthesis of appropriate acridine derivatives and their attachments to nucleic acids is described. In the nonenzymatic oligomerization of 2‐methyl‐1H‐imidazole‐activated guanosine 5′‐monophosphate, two observations deserve special notice: (1) reaction rates are almost unchanged by variations of the Na⁺ concentration; (2) the conformational type of the primer‐template duplex (A vs. B) has considerable influence on the rates and yields of RNA oligomerization. When the incorporation of cytidine was studied in the presence of 1M Na⁺ or K⁺, the process was almost inhibited by quadruplex formation of the oligo‐dG template. However, if these cations were omitted, an efficient primer extension could be observed using template concentrations as high as 100 μM. The chances for nonenzymatic self‐replication of RNA thus might be distinctly better than previously assumed.