To assess the generality of the geometric isomerization and to ensure the observed regioselectivity was not unique to BMIDA system 36, alternative dienes were first probed under model reaction conditions (Figure ). Exposing diene 1 to the photocatalyst and light irradiation for one minute resulted in a rapid isomerization, with identical regioselectivity to that of BMIDA substrate 36. The strategic incorporation of an α-methyl (41) and ortho substitutent (42), known to enhance isomerizazion via a buildup of 1,3-allylic strain, 23 also led to comparable alkene isomerization. These results instilled confidence that regiodivergence of the two EnT processes is general. To gain a deeper insight into the reaction profile we next carried out reaction monitoring (Figure ), quantifying the presence of starting material (E),(E)-41 (red), isomerization product (Z),(E)-41 (grey), and 2+2 cycloaddition product 43 (green). Analyzing the initial 15 minutes of the reaction revealed a rapid alkene isomerization process showing the clean conversion of (E),(E)-41 to (Z),(E)-41 with minimal 2+2 cycloaddition observed (Figure , i). However, running the reaction for an extended period demonstrated the depletion of (Z),(E)-41 and formation of cycloadduct 43 (Scheme 2B, ii). It is pertinent to note that during reaction monitoring, no other geometric isomers of diene starting material or product were detected and substrates with higher Z:E ratios were slower to undergo 2+2 cycloaddition, which aligns with recent advances in 2+2 reactions of imine derivatives. As a control (Z),(E)-41 was synthesized independently and exposed to the model reaction conditions (Figure ). Again, clean translation from (Z),(E)-starting material to geometrically pure E-isomer product was observed. Further controls were carried out demonstrating that the employed ruthenium catalyst does not facilitate a Z→E isomerization of the product styrene scaffold (See ESI for full details). Cyclic voltammetry ruled out possible single electron transfer providing further evidence of a sensitization activation mode (See ESI for full details). While, these seminal reaction probes unveil the systematic order in which reactivity occurs, rapid isomerization and slower subsequent 2+2 cycloaddition, they provide very little in distilling the origin of regiodivergence.