β-(1,3)-Glucans are widely distributed within microorganisms or seaweeds in which they act as membrane components or for energy storage, respectively. Since these glucans are not biosynthesized by mammals, they are likely to activate the immune system of their host. Since the discovery of their positive involvement as immunomodulator agents, numerous studies were published all around the glycosciences. These works deal with purification procedures, analytical chemistry, synthetic processes, chemical modification of the natural polysaccharides, determination of their physicochemical properties, and assessment of their biological and medicinal effects through in vitro and in vivo studies. This article aims at presenting some recent results linked to β-(1,3)-glucans through two closely connected points of view, i.e. biology and chemistry. Biological aspects will be focused more particularly on discovery of some receptors present on immunocompetent cells and scope and limitations of chemical synthesis and/or modifications will be described. Moreover, this paper will also introduce some new chemo-enzymatic synthetic methods using wild-type or mutant glycosidases and will be extended to novel opportunities of applications of β-(1,3)-glucans in nanotechnology resulting from a better understanding of their self-assembling propensity in aqueous media.