In the context of chemical or biochemical analysis, it is common to rely on molecular or biomolecular amplifications to improve the analytical performances of a detection method (i.e., sensitivity, limit of detection (LOD), analysis time, dynamic range of concentration, …). This is even more important when the targeted molecules or biomolecules are present at low concentrations. In most cases, molecular amplifications result from catalytic reactions wherein a molecule (either the analyte acting as a catalyst or a label catalyst revealing indirectly the presence of the analyte) triggers the catalysis of a reaction capable to generate a detectable signal (which can be optical, electrochemical, thermal, gravimetric, etc …). Under these conditions, the product linearly accumulates with time and the amplification factor depends only on the catalytic rate and reaction time. A popular example is the signal amplification resulting from the enzyme label involved in enzymelinked immunosorbent assays. However, greater molec-ular amplifications can be achieved by adequately combining the reactivity of different catalysts. One possibility is to cascade the reactivity of two catalysts, wherein a first one catalyzes the production of a second one. In such situation, the product of the secondary catalytic reaction accumulates quadratically with time. An even more powerful approach is to produce an exponential signal gain from an autocatalytic reaction, for which one of the products catalyzes its own formation. 12-14 A well-known example is the polymerase chain reaction, which through self-replication of a targeted DNA sequence allows the ultimate detection of a few molecules of nucleic acids in a few tens of microliters. While autocatalytic replication is well suited to nucleic acids, it is much more challenging to design for other molecules. Among the few examples of molecular self-replication strategies developed to date for the detection of small molecules is the dendritic chain reaction (DCR) first described in 2009 by Shabat and his collaborators. In this concept, the analyte triggers its self-replication through the decomposition of a dendritic molecular probe containing at least two masked equivalents of the analyte. This methodology was applied to the autocatalytic detection of H2O and fluoride ions. More recently, alternative strategies based on self-propagating thiolatedisulfide exchange, methionase chain reaction, or photoinduced autocatalysis were also reported. However, all these methods suffer from undesirable background reactions, which prevent the achievement of very low analyte concentrations. The main reason of these background reactions is the intrinsic lack of stability of starting coreactants, leading to self-initiation of the amplification cycle in the absence of analyte. Therefore, a critical issue is to design systems involving coreactants with high chemical stability and at the same time high reactivity and selectivity towards the trigger of the reaction. This is certainly the major challenge facing the exponential signal amplification strategies. An additional drawback is the slowness of the approaches proposed to date, sometimes requiring waiting several hours for an analytical response. To address these drawbacks and contribute to the development of alternative solutions, we recently proposed a new versatile molecular-based autocatalytic system in which the exponential gain is generated from cross-activation of two catalytic loops, as depicted in Scheme 1A. The first loop (Loop 1) is based on a H2O2-mediated deprotection of a boronate ester probe (P) to a hydroquinone derivative (QH2), which, in the presence of O2 in solution, spontaneously autoxidizes to a quinone (Q) with the concomitant regeneration of H2O2 (the latter acting thus as a catalyst in Loop 1). The autocatalysis is then engendered from the back conversion of Q into its reduced QH2 form in the presence of a reducing substrate S (or alternatively an enzyme/reducing substrate couple E/S), thus forming the second catalytic loop (Loop 2, which is also a redox cycle wherein Q/QH2 serves as a redox catalyst). Analytical derivations as well as numerical simulations of the kinetics of this redox cross-catalytic system allowed us to demonstrate the overstoichiometric production of H2O2 coupled with the exponential decrease of probe and substrate concentrations with time. This autocatalytic set is conceptually different from the previously reported branchedchain or self-propagating amplification reactions in that it does not require the design of a dendritic probe capable of releasing two or more equivalents of the trigger by self-immolation. Another advantage is that it offers the possibility to trigger the reaction either by H2O2 or any redox cycling compound, thus providing an extended degree of freedom to couple this molecular amplification not only to the detection of H2O2 (directly or indirect produced) but also to the detection of molecules exhibiting redox cycling properties (also either directly or indirectly generated).