Abstract
The design of porphyrin-based dendrimers featuring conjugated dendrons via alkene spacers herein demonstrates their important role in determining linear optical properties, as well as two-photon absorption (PA) and singlet oxygen photosensitising properties. Improvement in these properties compared to those observed for their analogous alkyne spacers makes these molecules appealing for combined 2-photon-based photodynamic therapy (PDT) and imaging.