Investigating the Photochemical Properties of a Clickable Silicon (IV) Phthalocyanine Core

Abstract In this study, a new azido‐functionalized silicon(IV) phthalocyanine ( SiPcN 3 ) was synthesized and comprehensively characterized, revealing its promising photochemical characteristics. Despite the common challenges associated with crystallizing phthalocyanine‐based compounds, SiPcN 3 was successfully obtained as single crystals in the monoclinic P 2 1 /c space group. The incorporation of ‐N 3 groups not only enhanced the compound's solubility and thermal stability but also introduced a reactive site suitable for future functionalization via copper‐catalyzed azide‐alkyne click chemistry. The molecular design enables straightforward integration into extended macromolecular systems, such as covalent organic frameworks (COFs) or cross‐linked polymers. UV‐Vis and photoluminescence analyses demonstrated intense Q‐band absorption in the red region and tunable emission characteristics. The measured singlet oxygen quantum yield (Φ Δ = 0.14) indicates moderate photosensitizing activity, but this performance can potentially be enhanced through appropriate derivatization, improving its applicability in photodynamic therapy (PDT). Overall, these findings position SiPcN 3 as a structurally versatile and functionally adaptable molecular platform, with promising potential for future development of PDT agents, photocatalytic/photooxidative materials, and optoelectronic devices, especially when embedded into porous or cross‐linked polymeric networks.