In this study, well-defined photoaffinity-based monoADPr probes (biotin-linked) were synthesized and used to study direct interactors of monoADPr. Either a benzophenone or diazirine group was incorporated to assess their performance in enriching for known mnonoADPr readers. To ensure only monoADPr readers were enriched and not proteins interacting with the linker and/or photocrosslinker, control probes were synthesized containing all but the monoADPr moiety.