1) Y. Hasegawa, H. Kawai, K. Nakamura, N. Yasuda, Y. Wada and S. Yanagida, Moleculaer design of luminescent Eu(III) complexes as lanthanide lasing medium and their optical properties, Rare Earths '04, Japan (NARA), 2004, Abst. No. FI-05.2) Y. Hasegawa, Radiative process control of asymmetric Eu(III) complexes for lanthanide lasing medium, Pacifichem 2005, USA (Hawaii), 2005, Abst. No. 153046.
3) Y, Hasegawa, Luminscent polymer containing Eu(III) complexes as lanthanide lasing medium, GIST/NAIST Joint symposium on Advanced Materials, Japan (NARA), 2006.
4) Y. Hasegawa, Polymer thin films containing symmetric Eu(III) complexes for lanthanide lasing medium, The 1st International Symposium on Luminescent Lanathanide Complexes (KISLLAM 2006), Korea (Daejeon), 2006.
5) Y. Hasegawa, Brilliant meterials constructed by rare-earth compounds with organic molecules, National Academics of Science & Engineering (NAS) and Japan Society for the Promotion of Science (JSPS), 10th annual Japanese-American Frontiers of Scinece Symposium (JAFoS), japan (Kanagawa), 2007.
6) Y. Hasegawa, Strategies for the design of luminescent lanthanide complexes, Global COE Program Center for Electronic Devices Innovation and Global seminar for Recent Development of Organic Devices and materials (I), Japan (Osaka) 2008.
7) Y. Hasegawa, Luminescent Polymer containing lanthanide complexes, 2nd International Symposium on Manipulation of Advanced Smart Materials (ISMAM2008), Japan (Hyogo), 2008.
8) Y. Hasegawa, Luminescence modulation in lanthanide(III) complex by coordination control of organic ligands, Asian International Symposium in Chemical Society of Japan, Japan (Chiba) 2009, Abst. No. 3F5-42.
9) Y. Hasegawa, Emission quantum yield measurements of luminescent lanthanide(III) complexes with narrow emission bands, 18th International Symposium on the photochemistry and Photophysics of coordination compounds (ISPPCC), Japan (Sapporo), 2009.
10) Y. Hasegawa, Brilliant Lantahnide Phosphors composed of Asymmetric Coordination Structures, International Symposium for Phosphor Materials 2009 in Niigata (Phosphor Safari), Japan (Niigata), 2009.
11) Y. Hasegawa, Characteristic Structures and Photophysical Properties of Europium(III) Complexes with Phosphine Oxides, Asian International Symposium in Chemical Society of Japan, Japan (Osaka) 2010, Abst. No. 3C4-38.
12) Y. Hasegawa, Luminescence Eu(III) complexes with asymmetric nide-coordination structures, International conference on frontier photoscience and functional materials (ICFPFM), Korea University (Sejoung), June 3-5, 2010.
13) Y. Hasegawa, T. Nakagawa, T. Kawai, "Luminescent lanthanide complexes with photo-switching units", First International Conference on Luminescence of Lanthanides (ICLL-1), Ukraine (Odessa), September 5-9, 2010.
14) Y. Hasegawa, "Europium chalcogenide nanocrystals with photo-magnetic properties", The 7th Korea-Japan Symposium on Frontier Photoscience 2010 (KJFP2010), Daegu, Korea, 2010, IL-21.
15) Y. Hasegawa, "Strong-luminescent materials containing asymmetric Eu(III) complexes", 17th Regional Symposium on Chemical Engineering (RSCE2010), Bangkok, Tailand, 2010, keynote lecture 4.
16) Y. Hasegawa; Lanthanide complexes with remarkable asymmetric dodecahedron structure, 19th International SPACC symposium, The society of pure and applied coordination chemistry (SPACC), Hokkaido Univ., L01, 2012.8.3-4 Plenary Lecture.
17) Y. Hasegawa; Brilliant Red-phosphors composed of of Eu(III) complexes with asymmetric coordination structures, KJF International Conference on organic Materials for Electronics and Photonics, Tohoku University, Sendai, IL3 Invited lecture (2013).
18) Y. Hasegawa; Luminescence and thermo-sensing properties of asymmetric lanthanide complexes, 3rd Japanese-german Joint Seminar Molecular Imaging Tehnology for Interdisciplinary Research, JAXA Chofu Aerospace Center, Tokyo. (2013). Keynote Lecture.
19) 2013.6.24 Y. Hasegawa, Luminescent lanthanide polymers for future phoytonic applications, National Taiwan University (Taipei).
20) 2013.11.25-27 Invited lecture: Y. Hasegawa; Remarkable luminescence of lanthanide coordination polymers, 2013 Korea-Japan Symposium on Frontier Photoscience (2013 KJFP), Seoul National University (Korea), IL-18.
21) 2015.4.23-25 Plenary lecture: Y. Hasegawa, : Lanthanide coordination polymers with photo-functional properties, International conference on Science, Technology and Applications of Rare Earths (ICSTAR 2015), Kerala state (India).
22) 2015.6.17-19 Invited lecture: Y. Hasegawa, : Brilliant Lanthanide Coordination Polymers for Full-color Imaging Appication, 1st International Conference on Advanced Imaging, National Center of Science, Tokyo, JAPAN.
23) 2015.6.26-28 Invited lecture: Y. Hasegawa; Lanthanide coordination polymers: control of their characteristic structures, The 11th Korea-Japan Symposium on Frontier Photoscience (KJFP 2015), Bareve Hotel, Jeju, Korea, IL05.
24) 2015.12.15-20 Invited lecture: Y. Hasegawa, Luminescent nanoparticles composed of lanthanide coordination polymers, 2015 International Chemical Congress of Pacific Basin Societies (Pacifichem2015), Hilton Hawaiian village Tapa Tower, Honolulu, Hawai (USA), 849.
25) 2016.6.5-10 Invited lecture: Y. Hasegawa; lanthanide coordination nanoparticles for novel luminescent materials, Rare Earths 2016, Hokkaido University, Sapporo, Hokkaido, Japan, I05-04.
26) 2018. 8.1-8.4. Invited talk, Y.Hasegawa, Luminescent dinuclear Eu(III)-Tb(III) complex with LMCT band for single-molecular thermosensor, 43rd International Conference on Coordination Cgemistry (ICCC)(Sendai,Japan), S06.
27) 2018. 9.3-6. Keynote lecture, Y.Hasegawa, Luminescent Eu(III) coordination polymers for efficient electroluminescence, 10th International conference on f-elements (ICFE10), (EPFL, Lausanne), KL-8-1.
28)2018.12.16-20. Invited lecture: Y. Hasegawa, Luminescent Eu(III) coordination polymers for organic EL devices, 10th Asian Photochemistry Conference (Haward Civil Service International House, Taipei, Taiwan).
29)2018.12.4-7.Invited lecture: Y. Hasegawa, Lanthanide coordination polymers with strong luminescent and photo-functional properties, The 12th SPSJ International Polymer Conference (IPC2018), Interenational Conference Center Hiroshima, Hiroshima, Japan)7G10IL.
30) 2018.11.12-14.Invited lecture: Y. Hasegawa, Europium coordination polymers for optical devices, 2018 Nankai International Symposium on Advanced Materials, (Nankai university, Tianjin, China).