In summary, this study enabled the 8-step synthesis of cyctetryptomycin A and B (1-2) through the dimerization of tryptophan derivatives using a newly developed Zr catalyst and macrocyclization employing CttpC. Previous reports have described similar reactions using Ni catalysts, (PPh3)3CoCl, V2O5, CuCl2, and PhI(OAc)2 reagents for the dimerization of tryptophan derivatives. However, some of these reaction conditions may be highly dependent on the brand, quality, and humidity of the location where the reaction is carried out, and implementation on a larger scale than a decagram was not realistic due to decreased yields. Additionally, some of the reaction conditions are stoichiometric rather than catalytic, making them extremely expensive and environmentally burdensome on larger scales. Furthermore, it is noteworthy to mention that while there are existing inexpensive methods available, some methods require highly acidic conditions, such as MsOH, which are not practically viable for large-scale synthesis due to safety concerns. In contrast, we provided herein a new option for the dimerization of tryptophan derivatives using an inexpensive, low-toxicity, mild condition, and non-hygroscopic Zr catalyst, which successfully synthesized 21 g of tetratryptomycin A (3). This method is applicable to not only tetratryptomycin A (3) but also many other bispyrrolidinoindoline-type natural products, offering a highly practical, reliable, and scalable technique that is not location-dependent. For the macrocyclization of tetratryptomycin A (3) using CttpC, we identified optimal reaction conditions on a gram scale, allowing for the 8-step synthesis of cyctetryptomycin A and B (1-2), which has not been reported previously. The significant advancements in genetic engineering techniques in recent years will likely enable the development of further optimized CttpCrelated artificial proteins in the future.