By combining precise analysis of extraterrestrial organic matter with replicated experiments, we will try to elucidate the initial chemical state at the time of the formation of the solar system. We will conduct comprehensive analyses of meteorites of asteroidal origin, interplanetary dust thought to have originated from comets, and organic matter in samples of the C-type asteroid Ryuguu brought back by the Hayabusa2 spacecraft to determine elemental (carbon, hydrogen, oxygen, nitrogen, and sulfur) and isotopic compositions, molecular structures, and so on. These organics were formed during the formation of the primitive solar system disk, and then transformed by heat, light, and water in the primitive solar system disk and small bodies to their current chemical state. From the minerals that coexist with extraterrestrial organics, we can infer the transformation processes that these organics went through, and constrain the chemical state (elemental composition, molecular structure, isotopes, and physical properties) of the early solar system organics before their transformation. We will conduct photochemical organic matter formation experiments simulating the irradiation of interstellar ices, as well as organic matter and silicate transformation experiments under protoplanetary disk and small body conditions, in order to constrain the chemical state (elemental composition, molecular structure, isotopes, and physical properties) of the first organic matter in the solar system before transformation. In particular, we will investigate the molecular species and their abundance ratios, which are known to be diverse in observations of the formation regions of planetary systems. In collaboration with the observation and theory groups, we will place the chemical processes in the early solar system and the chemical environment at the time of solar system formation in the diverse chemistry of the planet-forming region.