Chlorophyll in chloroplasts of higher plants mainly includes chlorophyll a and chlorophyll b. They are insoluble in water, but soluble in organic solvents such as ethanol, acetone, ether and chloroform. The molecular formula of chlorophyll a: C55H72O5N4Mg；; The molecular formula of chlorophyll b is C55H70O6N4Mg. In color, chlorophyll a is blue-green and chlorophyll b is yellow-green. Chemically, chlorophyll is an ester of chlorophyllin, which can undergo saponification reaction. Chlorophyll is a dicarboxylic acid, in which one carboxyl group is esterified by methanol and the other is esterified by phytol.

Chlorophyll molecule contains a "head" of porphyrin ring and a "tail" of phytol. Magnesium atom is located in the center of porphyrin ring and tends to be positively charged, while the nitrogen atom associated with it tends to be negatively charged, so porphyrin is polar, hydrophilic and can be combined with protein. Leaf alcohol is a diterpene composed of four isoprene units, and it is a lipophilic fatty chain, which determines the fat solubility of chlorophyll. Chlorophyll does not participate in hydrogen transfer or hydrogen redox, but only participates in energy transfer in the form of electron transfer (redox caused by electron gain and loss) and * * * yoke transfer (direct energy transfer).

The magnesium atom in porphyrin ring can be replaced by hydrogen ion, copper ion and zinc ion. When the leaves are treated with acid, hydrogen ions easily enter chloroplasts, replacing magnesium atoms to form pheophytin, which makes the leaves brown. The pheophytin is easy to combine with copper ions to form copper chlorophylls, and the color is more stable than before. People often treat green plant specimens with copper acetate according to this principle. Chlorophyll is a lipophilic aliphatic chain, which determines the fat solubility of chlorophyll molecules and makes it soluble in organic solvents such as acetone, alcohol and ether. Due to the structural differences, chlorophyll a is blue-green and chlorophyll b is yellow-green. It is easy to be oxidized and discolored under light. Chlorophyll is an ester of dicarboxylic acid and saponifies with alkali.

Chlorophyll is not very stable, and it will be decomposed by light, acid, alkali, oxygen and oxidant. Under acidic conditions, chlorophyll molecules can easily lose magnesium in porphyrin ring and become pheophytin. Chlorophyll solution can perform some reactions similar to photosynthesis, and make some compounds oxidized or reduced under light. The artificially prepared chlorophyll film can generate photoelectric potential and photocurrent under light, and can also catalyze some redox reactions.