The organ of the United Nations Organisation responsible for coordinating the work of its specialized agencies is the Economic and Social Council (ECOSOC).

Explanation:
The United Nations is an international organization founded in 1945 with the aim of promoting peace, security, and cooperation among nations. It consists of several organs, each with specific responsibilities. One of these organs is the Economic and Social Council (ECOSOC).

1. Role of ECOSOC:
- ECOSOC is responsible for coordinating the work of the specialized agencies, programs, and funds of the United Nations.
- It serves as a central platform for discussing international economic, social, and environmental issues.
- It plays a crucial role in fostering international cooperation and ensuring the implementation of the United Nations' goals and objectives.

2. Specialized Agencies:
- The United Nations has several specialized agencies, such as the World Health Organization (WHO), the United Nations Educational, Scientific and Cultural Organization (UNESCO), and the International Labour Organization (ILO).
- These specialized agencies have specific mandates and expertise in various fields, such as health, education, labor, and agriculture.
- They work towards achieving the objectives set by the United Nations and contribute to global development and cooperation.

3. Coordination by ECOSOC:
- ECOSOC acts as a coordinating body for these specialized agencies.
- It facilitates collaboration among the agencies and ensures that their activities are aligned with the overall objectives of the United Nations.
- ECOSOC reviews the programs and activities of the specialized agencies and provides guidance on their priorities and strategies.
- It also promotes cooperation between the agencies and other stakeholders, including governments, civil society organizations, and the private sector.

4. Other Responsibilities of ECOSOC:
- In addition to coordinating the work of specialized agencies, ECOSOC also addresses a wide range of economic, social, and environmental issues.
- It conducts studies, initiates discussions, and formulates policies on various topics, such as sustainable development, poverty eradication, and gender equality.
- ECOSOC plays a crucial role in shaping global development agendas and promoting international cooperation in these areas.

In conclusion, the Economic and Social Council (ECOSOC) is the organ of the United Nations responsible for coordinating the work of its specialized agencies. ECOSOC plays a central role in fostering international cooperation, ensuring the implementation of United Nations goals, and addressing economic, social, and environmental issues.

The Economic and Social Council is responsible for coordinating the work of its specialized agencies. It is one of the parts of the United Nations Organisation.