The photoreactivity of 1b (R = butyl, Fig. )), which has a higher melting point, was also investigated. Although 1b is a solid near room temperature (T m = 48.2 °C), it remains a liquid once melted (Tg = -51 °C). In its liquid state, 1b behaves as a Newtonian fluid with a viscosity (1.44 Pa•s at 20 °C) comparable to 1a (1.31 Pa•s) (Fig. , ESI †), making it suitable for comparative studies in both liquid and solid phases. Photoirradiation of liquid 1b at 10 °C led to microcrystalline aggregation similar to 1a. However, the reaction ratio was lower than that of 1a, with 22% unreacted IL persisting after 1 h (Fig. ), and the product contained ∼35% unidentified complexes alongside 2b (Fig. ). This inefficiency is likely due to partial crystallization during photoreaction, as supported by the quantitative formation of 2b when irradiated at 40 °C. Photoirradiation of solid 1b for 1 h resulted in a substantially low conversion (28%), yielding a heterogeneous solid-liquid mixture. Of the reacted product, 57 mol% formed the cubane complex 2b (Tdec = 317 °C), while the remainder consisted of unidentified complexes. The occurrence of the photoreaction, albeit with low conversion, despite being in the solid state, is probably due to benzene release and the formation of a minor liquid component (Fig. ).