The use of alternative waveforms for electric current delivery as a means to improve reactivity and selectivity has only recently been recognized in the field of synthetic organic electrochemistry. Early studies were suggestive that such an approach might have potential, despite having minimal benefit in synthesis. Whereas certain reactions have been shown to benefit from alternating current in terms of achieving higher reaction efficiency, drastic changes in product distribution were unknown. In 2021, the rAP waveform was shown to enable unique chemoselectivity in carbonyl reduction that could not be replicated in other ways, including both electrochemical and chemical means. Indeed, a completely different outcome was obtained by simply changing the waveform from direct current (DC) to rAP even when identical reaction conditions were employed. The same phenomenon was also applied to chemoselective Birch-type reductions wherein competing proton-reduction could be largely suppressed. Those prior studies both involved reductive processes and thus our attention pivoted to the Kolbe reaction, one of the most important oxidative electrochemical processes in need of a chemoselective variant. Towards this end, explorations began with 10undecenoic acid (1), a seemingly trivial biomassderived acid that is not amenable to Kolbe electrolysis (Table ). 2 However, its dimerization product (1,19-eicosadiene, 4) could have high utility as a novel polymer building block (vide infra). Despite its simple structure, the price of 4 is prohibitive for any practical use ($10,000/gram, Oakwood Chemical), whereas 1 is readily obtained from castor oil (~$20/kg). In good agreement with the prior report, 2 conventional conditions employing Pt electrodes with direct current electrolysis led to no observable formation of 4 (Entry 1), presumably due to electrode passivation (wherein the surface becomes insulating thereby blocking current from passing). Interestingly, the Kolbe reaction was previously studied with an AC waveform, and the detailed result was published in 1939 by Shipley and Rogers. In this report, no notable difference between DC and AC was observed on the reaction outcome, consistent with our findings that 4 was not formed in either case (Entry 1 and 2). Altering the base, solvent as well as electrode under DC electrolysis gave no improvement on the product formation (Entry 3 and 4). Remarkably, simply switching the waveform from DC to rAP under the identical conditions of entry 4 led to formation of 4 in 63% isolated yield (Entry 5). The reaction proceeds using technical grade acetone as solvent without any precaution to remove water and employs only catalytic amount of inexpensive Me4N•OH as a soluble base along with carbon-based electrodes (RVC, reticulated vitreous carbon). On a small scale, an Ar or N2 balloon is employed but this precaution is not necessary on larger scales (vide infra). It is particularly surprising that Pt electrodes are not required, since Pt has, for over a century, been considered as essential for radical-based Kolbe reactivity. In fact, carbonbased electrodes are known to promote carbocation reactivity instead, leading to Hofer-Moest products. Although Me4N•OH is available in bulk quantity and widely used in silcon-etching, it can also be replaced by the even less expensive base KOH (Entry 6). An organic base (Et3N) and other solvents were found to deteriorate the reaction, probably due to competing oxidation (Entries 7-9). The beneficial role of acetone is attributed to its ability to act as an electron-and proton acceptor to balance oxidative decarboxylation, which is supported by the detection of isopropanol in the crude mixture (Fig. ). The optimum frequency for rAP-enabled reactivity is 50 ms (e.g. Entry 5), but a lower frequency is also effective (Entry 10). Finally, the use of a conventional sinusoidal AC waveform under otherwise identical conditions showed a similar effect with rAP, albeit with lower reaction efficiency that is consistent with previous reports (Entry 11). Before exploring the scope of the rAP-Kolbe reaction, 4-phenylbutyric acid (2, Table ) was also evaluated due to its documented tendency to undergo arene oxidation that leads to the benzylic functionalization in addition to productive dimerization to 7. Indeed, under conventional Kolbe reaction conditions with Pt electrodes (Entry 1) the reaction was discontinued due to electrode passivation, whereas arene oxidation products (5 and 6) were predominant with RVC electrodes regardless of the current density (Entries 2 and 3). In stark contrast, the rAP-Kolbe reaction led to the desired dimer 7 in 70% isolated yield without detectable amount of arene oxidation (Entry 4). With a general protocol in hand, the scope of chemoselective rAP-Kolbe reaction was explored as illustrated in Table . In broad terms this reaction is ideally suited towards the coupling of primary carboxylic acids, as secondary and tertiary systems mainly lead to Hofer-Most reactivity (see Supporting Information for details). Performing the reaction with DC instead of rAP is detrimental as indicated in the table. Unlike the classic Kolbe reaction, this reaction tolerates several synthetically useful functional groups such as esters (8-10,16,18), carbamates (11, 17, 18, 19), free hydroxy (12), ketones (13), both electron-deficient (15) and rich arenes (16), aryl halides (15), and terminal and internal olefins (4, 14). Presumably due to the free radical nature of the Kolbe reaction, the hindered neopentyl unit can also be readily coupled to afford diester 10 in 69% yield.