Molecules with all-carbon tetrasubstituted alkene structural motifs, such as the estrogen receptor modulators tamoxifen and idoxifene, amongst others (Figure ), have displayed significant biological activity and found widespread applications in the pharmaceutical industry. Moreover, their unique photoand electrochemical properties have rendered them particularly useful for molecular switches and material science. Despite this rising demand, the stereoselective synthesis of tetrasubstituted alkenes has been a longstanding challenge and as a result only a few synthetic approaches have been reported in recent years. While key progress in this field has been achieved by employing traditional olefination methods, these transformations often suffer from low atom-economy and poor stereoselectivity. One of the most commonly applied synthetic strategies is the carbometalation of internal alkynes, followed by a metal-catalyzed cross-coupling. This elegant approach has set the stage for a plethora of useful tetrasubstituted alkene syntheses, but is often associated with serious limitations regarding stereocontrol and functional group tolerance. In addition to the utilization of oxidative Heck couplings, more recent examples have showcased that cross-couplings of tetrasubstituted alkenyl electrophiles comprise an attractive alternative to tradition alkene coupling reactions. However, a vast majority of these transformations are structurally limited to α,β-unsaturated compounds, such as acrylates and ketones. In contrast, highly stereoselective methods for the assembly of unactivated acyclic tetrasubstituted alkenes have remained scarce. In 2017, our group reported a two-step synthesis of tetrasubstituted alkenes, in which the stereochemical outcome is set by diastereoselective preparation of the enol tosylate starting material, followed by a stereoretentive Pd-catalyzed Suzuki-Miyaura cross-coupling (Figure ). Although this protocol allowed for the highly selective synthesis of (E)-alkenes, the selectivity was largely governed by the tosylation step and ultimately limited access to (Z)-alkenes, whose precursor tosylates were less accessible in high diastereomeric purity. Capitalizing on seminal studies of stereodivergent Pd-catalyzed cross-couplings of disubstituted alkenyl halides by Lipshutz, we set out to develop a stereoselective cross-coupling reaction that does not rely on the geometry of the starting material and gives expedient access to stereodefined tetrasubstituted alkene products. Herein, we report a ligand-controlled Ni-catalyzed synthesis of stereodefined tetrasubstituted alkenes from either a single enol tosylate diastereomer in a stereodivergent process, or, alternatively, from a diastereomeric mixture of starting materials in a stereoconvergent manner (Figure ). It is important to note that either product diastereomer can be generated under the stereodivergent/-convergent regimes by simply switching the ligand and solvent system. The diastereo-convergent reaction is highlighted in this report due to its synthetic utility, as it obviates the need for stereoselective starting material preparation, which is particularly challenging for the corresponding (Z)-configured enol tosylates. An optimization study was designed by using kraken, a computational database of >1500 phosphorus ligand descriptors, to identify a diverse set of phosphines to evaluate, which enabled the identification of reaction conditions for Ni-catalyzed Suzuki-Miyaura cross-coupling. The optimized conditions were then applied to the synthesis of a variety of tetrasubstituted alkene scaffolds in typically high diastereomeric ratios of up to ~90:10 E/Z and Z/E. Notably, the unique mechanistic features of this catalytic transformation contrast the thermodynamic control of previously developed convergent cross-couplings for the synthesis of di-and trisubstituted alkenes, which typically proceed via metal-hydride catalyzed isomerizations. Our mechanistic hypothesis is supported by a combination of DFT calculations and experimental insights to shed insight into the elusive isomerization step that has previously been observed in several cross-coupling reactions of alkenyl electrophiles.