The photoreactions of $ReH_5(Cyttp);(1);(Cyttp=PhP(CH_2CH_2CH_2PCy_2)_2);with;CO,;CO_2;and;PMe_3 has been investigated to find the differences in reactivities from those of trismonophosphine analog. Irradiation of 1 under CO, $CO_2$ and excess $PMe_3$ in benzene results in the formation of the complexes, $ReH(CO)_2(Cyttp);(2),;ReH_2({eta}^2-HCO_2)(Cyttp);(3);and;$ReH_3(PMe_3)(Cyttp)$ (4), respectively. The resulting products suggest that photoreactions of $ReH_5(Cyttp)$ proceed by photoextrusion of $H_2$ giving a phototransient species "$ReH_3$(Cyttp)" which can be trapped by CO, $CO_2;and;PMe_3$. The structures of 2, 3 and 4 are inferred based on $^1H,;^{31}P$ NMR and I. R spectroscopy.