Unexpectedly, all the photocatalysts tested proved capable of catalysing the reaction. Unactivated halides are known to have more negative reduction potentials (e.g. ethyl iodide: 𝐸 1/2 red = -1.67 V vs SCE ) than activated iodides (α-carbonyl, α-heteroatom, benzylic or allylic) and therefore normally require strongly reducing photocatalysts for efficient radical formation. The higher reactivity of this substrate may be due to the inductive electronic activation provided by the siloxane substituent. No clear distinction in the yield was seen between photocatalysts typically going through oxidative (Table , entries 1-6) and reductive (Table , entries 7-10) quenching pathways, nor between metal-based (Table , entries 1, 8-10) and organic (Table , entries 2-7) photocatalysts. In line with previous reports of atom transfer radical addition of activated halides with alkenes and alkynes, complete conversion from 4a to 5a generally proceeded faster with photocatalysts that go through reductive quenching. 4CzIPN (Table 1, entry 7) was selected as the most promising photocatalyst due to its fast reaction time and high yield.