A series of rhodium-based complexes were explored theoretically to understand their application in optical materials and potential photocatalytic activity. Better structural description of [RhAu(CNH)2(PH2CH2PH2)2]2+ (1) were achieved with the ab initio MP2, XαVWN, and SVWN methods. To fine-tune the electronic spectroscopy, two analogues of 1 were taken into account by varying its Au metal center and bridging bidentate ligand. The experimental spectra were well reproduced by our TD-DFT calculations. It was shown that the lowest-energy absorption of homobimetallic Rh-Rh complex occurs in lower-energy region than those of heterobimetallic Rh-Au complexes.