The present invention relates to photo-labile pro-fragrance conjugates comprising: a) a photo-labile unit which upon exposure to electromagnetic radiation is capable of releasing a pro-fragrance unit; and b) a pro-fragrance unit, which when so released is either i) a pro-fragrance compound capable of releasing a fragrance raw material; or ii) a fragrance raw material. The present invention relates to systems for delivering fragrances to a situs, and to laundry detergent compositions, fine fragrances, personal care and hair care compositions comprising said systems.