CuInSe2 monograin powders (MGP) were synthesized from Cu-In alloys of different Cu/In concentration ratios and elemental Se in liquid phase of flux material in evacuated quartz ampoules. The surface morphology, phase structure, and composition of the powder crystals were analyzed by scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis respectively. Bulk composition was analyzed polarographically. Photoluminescence spectra were measured at 9 K. It was found that the composition of MGP material (Cu/In concentration ratio) can be controlled by the concentration ratio of precursor Cu-In alloys. Single phase CuInSe2 growth is realisable between 0.7<Cu/In<1 at the growth temperature of 1000 K. Photoluminescence spectra of near-stoichiometric materials had one dominant peak at 0.93 eV, which is typical to In-rich CuInSe2. Samples with high In content exhibited two broad bands with peak positions at 0.86 and 0.93 eV.