**4. Thematic analysis**

Concepts within themes were chosen to identify the key themes and ideas that emerged from the systematic review of the studies. In these investigations, which

present concepts as spots and themes, concepts that regularly travel together come up together intensely and are exhibited close together. The most used notion within each theme serves as the basis for the names of the themes in the final concept. The most significant topics that emerged from our analysis of the links between leadership and innovation include innovation, innovation performance, innovative work behavior, and innovativeness, as shown in **Table 1**. **Table 1** also includes illustrations of the primary themes and their hits. The main themes, apart from the themes of potential, industry, and analysis, involve other ideas and are related to one another in various ways. The analysis reveals that one of the primary themes examined in 29 studies, particularly transformational leadership, and transactional leadership, has a substantial relationship with innovation performance. While the relationship between leadership and innovation was studied in 17 papers. The investigation discovered 13 studies that looked at the relationship between innovative work behavior and leadership. The words "leadership," "green innovation," "relationship," "sustainable," and "employees" also appear as concepts, indicating a strong relationship between leadership practices and employee green innovation and sustainable innovation, even though the sub-theme of "green innovation and sustainable innovation" includes the adjective "strong." Green appears to serve as a connecting factor between organizational change and environmental innovation, which promotes the growth of sustainable innovation. The idea of sustainability also supports a strong and direct relationship between leadership and innovation. Although the concepts of leadership and green innovation and the concept of performance do not directly relate to one another, it is obvious that leadership can have a substantial impact on innovation performance through the chain reaction of these concepts.

On the other hand, the theme of sustainable innovation and the ideas of study, impact, and data are related to leadership, and these connections help to interpret the function of innovation in the business process. It is also obvious that research on the possible effects of innovation will probably give practitioners useful information. It has been demonstrated that businesses can alter their behaviors by adopting green standards, which helps to attain sustainable innovation performance, and that sustainable innovation has an indirect relationship with leadership via change. The intersection of leadership and green innovation is supported by a link between sustainability, innovation, and green themes, according to the thematic analysis. As may be predicted, research on leadership, innovation, and sustainability predominates, but studies on green innovation have yet to garner the attention they merit. Therefore, to increase understanding of green adaptive behaviors in companies, future studies should concentrate on green creativity and its antecedents in the service sectors. The analysis found that prior research covered a wide range of topics related to innovation through leadership. These themes were further developed in our review with the goal of methodically filling this knowledge gap. These studies concentrated on the ways in which leadership affects innovation. Leadership philosophies and innovation performance were examined by Gallego-Nicholls et al. [92] and Al-Diery et al. [93]. The effectiveness of innovation was positively impacted by transformational, transactional, laissez-faire, empowering, servant, and visionary leadership styles (innovation, innovativeness, innovative work behavior, sustainable innovation, and green innovation). Leadership philosophies and innovation performance were examined in 27 studies. Innovation and leadership were associated in 13 studies. 11 studies show a connection between innovative workplace behavior and leadership styles. The results demonstrate that both transactional and transformative leadership are useful for innovation. According to studies, other leadership philosophies such as laissez-faire, servile, and autocratic are ineffective.
