Dr. N. Sasidharan worked as a Scientist at the Kerala Forest Research Institute, Peechi, Thrissur, during the period 1977–2012. He served as Programme Co-ordinator of the Forest Ecology and Biodiversity Conservation Programme Division and superannuated from service on 31 August 2012. His major research interests include Systematic Botany, Ecology and Non-Wood Forest Products (NWFPs). He carried out extensive studies on the sustainable extraction of NWFPs, quantitative inventory of non-wood forest produces, mass multiplication and agro-technology of medicinal plants, phytochemical screening and evaluation of biological properties, assessment of raw drug consumption and requirements of the Ayurvedic medicine industry, and ethnobotanical studies among forest-dwelling tribal communities. He worked extensively on forest flora, particularly the wildlife sanctuaries and forest trees of Kerala. He developed a DVD on the flowering plants of Kerala consisting of 5,094 species in 2011 and designed a Tree Identification Key for the forest trees of Kerala covering 650 tree species based on field and vegetative characters in 2007. He has published 46 research reports, 7 books, 115 scientific papers and 12 popular articles, and has described 26 new species including 7 tree species.

Dr. Sasidharan obtained his Ph.D. in Botany from the University of Calicut in 1993 for his thesis Forest Flora of Thrissur District under the guidance of Dr. V. V. Sivarajan. He received an International Diploma from the Royal Botanic Gardens, Kew, England in 1995. He was awarded the Dr. V. V. Sivarajan Gold Medal by the Indian Association of Angiosperm Taxonomists in 2004 and the Dr. B. P. Pal Fellowship of the Ministry of Environment and Forests, Government of India, in 2010 for outstanding contributions in the field of biodiversity. He also served as Emeritus Scientist of the Kerala State Council for Science, Technology and Environment, Government of Kerala, during the period 2014–2017. From February 2018 to 2023 April, he worked as Project Dy. Regional Director of the Regional Cum Facilitation Centre Southern Region of National Medicinal Plants Board.