Abstract: A heat sensitive recording material comprising (A) a color forming substance, (B) a developer capable of bringing the color forming substance into color image by heating and (C) a binder, characterized in that the component (B) comprises at least one diphenyl compound having the formula (I): ##STR1## The heat sensitive recording material can give satisfactory color sensibility, color density and printability in recording process at low temperature and high speed compared to conventional heat sensitive recording materials. Further, there are wholly observed the black fog on the surface of recording paper before recording and the black spot in contact with diazo photosensitive papers.