Despite the growing promise of bacterial therapy, due to the tumor targeting effect, in solid tumor treatment, most conventional therapeutic bacteria exhibit pathogenicity and insufficient therapeutic efficacy in the tumor milieu. Here we show the optical characterization of non-pathogenic natural purple photosynthetic bacteria (PPSB), which displays multifunctionality and biocompatibility in the treatment of highly active cancers. To this end, the living PPSB are applied in cancer theranostics, using bio-optical-window I and II near-infrared (NIR) light. PPSB exhibit strong NIR-I-to-NIR-II reporter fluorescence, powerful photothermal conversion, excellent reactive oxygen species generation, and contrasting photo-acoustic effects, via the energy transfer system of light harvesting nanocomplexes in PPSB membranes, making PPSB useful for highly targeted tumor elimination and precisely marking tumor location with the help of immune system. Furthermore, short-term fasting, that can evoke anticancer immunological reactions, could dramatically improve the optical efficacies of the bacterial treatment. Starving-mediated and NIR light-driven PPSB would serve as an effective “all-in-one” theranostic material for use in deep tumor treatments.