Chlorophyll is the green pigment that plants use to absorb light energy for photosynthesis. While plants are the most well-known organisms containing chlorophyll, it's not exclusive to them.

Here are the types of organisms that contain chlorophyll:

* Plants: This includes all types of plants, from tiny algae to towering trees. They use chlorophyll to convert sunlight, water, and carbon dioxide into food.

* Algae: This diverse group of organisms includes single-celled algae like diatoms and multicellular algae like seaweed. They are important primary producers in aquatic ecosystems.

* Cyanobacteria: Also known as blue-green algae, these bacteria are photosynthetic and play a crucial role in oxygen production.

* Some Protists: Certain single-celled organisms like Euglena contain chlorophyll and are able to perform photosynthesis.

Important Note: It's crucial to understand that not all organisms that are green necessarily contain chlorophyll. Some organisms might have pigments like carotenoids that give them a green appearance, but they are not photosynthetic.