New multifunctional blue-emissive materials with superior thermal properties, viz., 4,4′-bis(1-(4-naphthyl)-1 H -phenanthro[9,10- d ]imidazol-2-yl)binaphthyl (NPIBN), 4,4′-bis(1-(4-cyanonaphthyl)-1 H -phenanthro[9,10- d ]imidazol-2-yl)biphenyl (CNPIBP), and 4,4′-bis(1-(4-cyanonaphthyl)-1 H -phenanthro[9,10- d ]imidazol-2-yl)binaphthyl (CNPIBN) have been synthesized. The said molecules show high photoluminescence quantum yield (Φ s/f : NPIBN-0.75/0.68, CNPIBP-0.85/0.76, and CNPIBN-0.90/0.88). The fabricated nondoped/doped device with CNPIBN/4,4′-bis(carbazol-9-yl)biphenyl: CNPIBN display maximum efficiencies (η ex 4.96/5.4%; η c 7.46/7.56 cd A –1 ; η p 6.85/6.91 lm W –1 ) at low turn-on voltage (3.5/3.8 V). Nondoped devices based on D−π–A architecture, 4-(2-(5-(9 H -carbazol-9-yl)thiophen-2-yl)-1 H -phenanthro[9,10- d ]imidazol-1-yl)naphthalene-1-carbonitrile exhibit maximum efficiencies (η ex 2.32%; η c 4.00 cd A –1 ; η p 3.42 lm W –1 ) compared to 4-(2-(5-(4-(diphenylamino)phenyl)thiophen-2-yl)-1 H -phenanthro[9,10- d ]imidazol-1-yl)naphthalene-1-carbonitrile (η ex 2.01%; η c 3.89 cd A –1 ; η p 3.15 lm W –1 ).

Efficient blue emitters, 1-(2,3-dihydrobenzodioxinyl)-2-naphthylphenanthroimidazole, 1-(2,3-dihydrobenzodioxinyl)-2-methoxynaphthylphenanthroimidazole and 1-(2,3-dihydrobenzodioxinyl)-2-pyrenylphenanthroimidazole have been reported.

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The CADPPI:Ir(ppy)3 device exhibits L – 90 12 cd m−2; ηex – 18.8%; ηc − 27.3 cd A−1; ηp – 29.8 lm W−1; CIE (0.30, 0.60).

The Cz-DEPVI device showed high efficiencies of L: 13955 cd m−2, ηex: 4.90%, ηc: 6.0 cd A−1, ηp: 5.4 lm W−1 and CIE coordinates of (0.15, 0.06) at 2.8 V.