Ending the introduction with the main idea or thesis statement is important because it brings clarity, guides the reader, captures attention, promotes coherence, and enhances persuasiveness. It provides a clear and concise statement that outlines the central focus or argument of the piece, allowing the reader or audience to understand the main point being made. It serves as a roadmap for the rest of the piece, informing the reader or audience about what to expect and how the subsequent content will support or develop that main idea. By capturing attention, it sets the tone and generates interest in the piece. It ensures coherence by connecting subsequent content to the central idea, preventing confusion or digression. Lastly, it adds persuasiveness by presenting a strong and focused claim, allowing the writer or presenter to assert their stance or argument with conviction and authority. Overall, ending the introduction with the main idea or thesis statement improves the effectiveness of communication with the reader or audience.