This research presents a new group of type I photoinitiators, including 1,1-dimethoxy-1-phenylpropan-2-one and its derivatives. Due to their extended conjugation system, their absorption is significantly red-shifted, allowing activation even at 470 nm. The use of aldol condensation enabled the synthesis of a library of new compounds for photopolymerization processes. The developed photoinitiators effectively initiate the free-radical polymerization of acrylate and methacrylate monomers, making them suitable for 3D printing applications. Their properties also facilitate the efficient preparation of nanocomposites via vat 3D printing, representing a significant advancement in the development of one-component photoinitiators active under visible light.