The reported examples allowed formation of a second C-C bond including a C(sp 3 ) or C(sp 2 ) carbon. However, there is no example of a C(sp 3 )-C(sp) bond formation. Alkynes are versatile functional groups with applications in various fields such as medicinal chemistry, chemical biology and materials science. Along the various radical approaches developed over the years to access alkynylated compounds, ethynylbenziodoxolones (EBXs) have been shown to be efficient radical traps. Furthermore, Leonori and coworkers have shown that EBXs can be used to terminate photoredox-catalyzed radical cyclization-alkynylation cascade reactions. In our previous work on the alkynylative deoxygenation of cesium oxalates, we had observed a single example of cyclizationalkynylation on a pre-organized rigid substrate. Herein, we introduce a general method for the synthesis of -lactones andlactams starting from easily-accessible homoallylic cesium oxalates using an organic dye and EBXs as radical traps through an efficient lactonization-alkynylation cascade (Scheme 1E). Based on previous reports on photomediated alkynylation, we started our investigation using homoallylic cesium oxalate 2a as starting material, 1.5 equiv. of PhEBX (3a) as SOMOphile and 5 mol% 4CzIPN (4a) as photocatalyst (Table ). After irradiation (44 W, 440 nm) in DCM overnight, the desired spirolactone 5a was obtained in 53% yield (entry 1). Changing the photocatalyst for the more oxidizing 4ClCzIPN (4b) provided 5a in 64% yield (entry 2). The chlorinated solvent could be replaced by DMSO without change in yield (entry 3). In order to avoid polymerization of the starting material 2a, lowering its concentration to 0.05 M and the catalyst loading to 2%, while keeping the concentration of PhEBX (3a) to 1.5 M provided spirolactone 5a in 75% yield (entry 4). The yield could be further improved to 80% by lowering the power of the light source to 22 W and stirring the reaction for 42 h (entry 5). Finally, when the reaction was performed in absence of any photocatalyst, 5a was obtained in 14% yield due to the innate photoactivity of PhEBX (3a) (entry 6). In absence of light no product was observed (entry 7). With the optimized conditions in hand, we first investigated the scope of the lactonization reaction on tertiary alcohols to obtain valuable spirolactones (Scheme 2A). The model substrate 2a cyclized smoothly on 0.3 mmol scale, giving 5a in 76% isolated yield. Furthermore, performing the same reaction on 3.0 mmol scale provided 5a in 69% yield. Spiroheterocycles 5b and 5c were obtained in 86% and 70% yield, respectively. The size of the second ring in the spirocycle could be varied broadly to give compounds 5d, 5e and 5f in 77%, 81% and 74% yield, respectively. The dehydroepiandrosterone-derivated spirolactone 5g was obtained in 50% yield and 3:1 dr. Having established the scope of tertiary alcohols, we moved our attention to secondary homoallylc cesium oxalates (Scheme 2B). This class of substrates had not been investigated by Overman and co-workers. Lactone 5h having a pendent alkyl chain could be isolated in 55% yield and 3:2 dr. Furthermore, performing the reaction from trans-1,2-vinyl-cyclohexanol provided the trans 6/5 fused lactone 5i in 56% yield and perfect diastereoselectivity. Additionally, the bridged compound 5j was isolated in 25% yield as a single diastereoisomer. Finally, the alkynyl-lactonization reaction was performed on primary homoallylic cesium oxalates (Scheme 2C). We used this class of substrates to study the difference in reactivity of the primary, secondary or tertiary radical intermediate formed after cyclization in the alkynylation step. In the case of C(sp 3 )-C(sp 2 ) bond formation, only primary intermediates had been reported. Lactone 5k resulting from alkynylation of a primary radical intermediate was obtained in 62% yield, while a cis-hexenolderived cesium oxalate cyclized in 70% yield and 4:3 dr through the alkynylation of a secondary radical to give 5l. Lactone 5m, which arose from a tertiary radical intermediate, was isolated in 40% yield. We speculate that the trapping of the radical with PhEBX (3a) was less efficient in this case due to steric congestion.