A series of phenanthroline-based ligands have been synthesized and their influence as N ligands in heteroleptic [Cu(P^P)(N^N)]+photosensitizers in light driven water reduction has been studied.In this noble-metal free Cu-Fe-based photocatalytic water reduction system,the structure effect of this N ligands has been explored by a previously developed in-situ method and the complexes exhibited a significant hydrogen generation with up to 1388 turnover numbers(TONCu).The steric function and electron effect of 2,9 and 4,7 positions substituent groups in phenanthroline were discussed for the complexs activity in detail.