In the synthesis of all-silica zeolite beta, dehydration of the initial mixture at 80 °C resulted in the partial decomposition of tetraethylammonium hydroxide to generate triethylamine via the Hofmann degradation reaction. The control experiments showed that the presence of triethylamine was needed for the enrichment of polymorph A. Without the presence of triethylamine, only normal zeolite beta can be obtained. Replacing the triethylamine with other monoamines such as diethylamine, n-butylamine, n-propylamine, cyclohexylamine, and ethylamine can also promote the enrichment of polymorph A. However, diamines such as ethylenediamine and 1,2-diaminopropane as the second amine failed to enrich the polymorph A. With this co-template strategy, the synthesis cost of polymorph A-enriched zeolite beta can be significantly reduced by lowering the usage of expensive tetraethylammonium hydroxide and using cheap monoamines. The reason the monoamines promoted the enrichment and diamines failed to promote the enrichment of polymorph A is under further investigation.