The　pi-conjugated　molecules,　anthracene,　pyrene　and　perylene　with　stepwise　enhanced　conjugation,　have　become　a　key　ingredient　in　the　design　of　new　organic　semiconductors　for　light　emission　and　energy　harvesting　applications.　Here,　new　biphenyl　dissubstituted　anthracene,　pyrene　and　perylene　derivatives　are　synthesized　and　investigated　as　blue-emitting　materials.　The　designed　molecules　exhibited　typical　amplified　spontaneous　emission　(ASE)　behavior　in　solid　thin　films　for　the　compounds　dispersed　in　the　inert　polystyrene　host　at　a　rather　large　(5　wt%)　chromophore　concentration.　Theoretical　analysis　assists　in　understanding　the　emission　properties　and　optical　gain　performance.　The　calculations　reveal　enhanced　transition　density　and　increased　transition　dipole　moment　accompanying　by　stepwise　enhanced　molecular　conjugation　of　fluorophore-cores.　In　addition,　enhanced　fluorescence　quantum　yield,　significant　shortened　fluorescence　lifetimes　and　increased　radiative　decay　rate　for　designed　compounds　promote　the　occurrence　of　ASE　behavior　compared　with　anthracene,　pyrene　and　perylene.　As　well,　the　vibration　analysis　show　that　the　intramolecular　vibrational　modes　of　researched　molecules　possessed　small　Huang-Rhys　factors,　which　thus　bring　in　effective　competition　between　radiative　and　non-radiative　decay　process　in　favor　of　optical　gain.　The　experimental　and　theoretical　provide　evidence　that　the　reported　molecules　are　promising　candidates　for　organic　laser　applications.