A blue phase liquid crystalline material comprising a mixture comprising at least one bimesogenic compound and at least one chiral compound, wherein the material is capable of stable existence in the blue phase over a temperature range of at least 5.degree. C. A process for the preparation of the above blue phase liquid crystalline material, an optical device comprising it, a process of mirrorless lasing and a slotted monolithic optical waveguide using it are also disclosed.