Photophysical and photochemical measurements have been made on a series of novel non-peripherally octa(alkyl-substituted) zinc phthalocyanines. Fluorescence quantum yields and lifetimes, triplet quantum yields and lifetimes and singlet delta oxygen quantum yields were measured in 1% v/v pyridine in toluene. The effects of alkyl substituents and increasing chain length relative to the unsubstituted parent molecule, zinc phthalocyanine (ZnPc), are discussed. ZnPc with alkyl substituents of chain length 5–15 carbons exhibited similar absorption and emission maxima (704 nm and 718 nm respectively) with the molar absorptivity of the Q-band [similar]105 M-1 cm-1. The series of compounds also exhibited triplet quantum yields of 0.78–0.84 and singlet oxygen quantum yields of 0.67–0.71.