We report the synthesis and characterization of I–III bimetallic complexes (Ph3P)2M(µ-SEt)2E(SEt)2 (M = Cu, Ag and E = In, Ga, Al), as well as (Ph3P)2M(µ-Cl)2ECl2 complexes isolated during their syntheses. The thiolate complexes can be used as single-source precursors (SSPs) to prepare various I–III chalcogenide semiconductor materials. The preparation of some SSPs of the series required minor variation in the reaction conditions. The organometallic complexes were structurally characterized by X-ray diffraction. The SSPs are compared in terms of their solid-state structures, basic reactivity, and potential suitability as precursors for chalcopyrite materials.