Green tris-(8-hydroxyquinoline)aluminum is one of the most useful metal chelates for organic light emitting diodes (OLEDs). By changing 5-position CH to N and adding methyl or phenyl substituent on 4- and 6- position of 8-hydroxylquinoline, a series of blue light-emitting metal (Al3+, Ga3+, In3+, Mg2+, Zn2+, or Hf4+) chelates 4-methyl-[1.5]-naph- thyridin-8-ol (mND), 4,6-methyl-[1,5]-naphthyridin-8-ol (mmND), and 8-methyl-2-phenyl-[1,5]naphthyridin-4-ol (mpND) were successfully synthesized and characterized. These new metal chelates are all blue to deep blue fluorescent and are suitable for wide band-gap host material for efficient dopant-based blue OLEDs and white OLEDs.