A thermomechanical analysis (TMA) study, directly on a bonded joint during the process of adhesive hardening, on the sinergy and interference between polycondensation and autocondensation on procyanidin, and profisetinidin-prorobinetinidin-type polyflavonoid tannins network formation and hardening, confirmed that also at the higher curing temperatures characteristic of the hardening of tannin-based wood adhesives, hardening by polycondensation can be coupled with simultaneous hardening of tannins by autocondensation. Some coreactants appear to depress the tannin autocondensation while still leaving a small contribution of this reaction to the formation of the final crosslinked network. Other coreactants instead appear to enhance formation of the final network by sinergy between the 2 condensation mechanisms, while still others do not show any interference between the 2 types of reaction.