The European Green Deal focuses on investment which will mobilise at least €1 trillion of sustainable investments and development of an ‘enabling framework’ which will facilitate and stimulate the transition to a climate-neutral, green and inclusive economy while ensuring companies report their sustainable activities. This thesis focuses on two-strands, financing of Clean Technology (Cleantech) firms and sustainability reporting. The analysis is presented in four studies. Study 1 analyses the financing of Cleantech firms that raised equity crowdfunding on platforms in Europe. Crowdfunding has a positive impact on innovation and growth opportunities of Cleantech firms, and in the post-crowdfunding period firms raise significantly greater amounts of external equity, suggesting signalling effects. Study 2 examines equity funding of Cleantech firms in the UK. 739 firms are analysed through the lens of the pecking order theory. A primary finding is that firms with lower intangible assets are more likely to raise equity funding. The study questions the restrictiveness of IAS 38 and the patient capital gap for Cleantech firms. Study 3 investigates the feasibility, potential and financial implications of environmental sustainability reporting. The study analyses the views of 203 Small-to-Medium sized accounting practitioners (SMPs). The greatest perceived benefit for firms adopting sustainability reporting is an improved company image. Respondents detail resourcing implications, providing an estimate of the additional cost. An impediment in implementing sustainability reporting is the lack of knowledge and training, not only for small firms but also for accounting professionals. Study 4 investigates the challenges and the non-regulatory benefits and incentives for SMEs to engage with the EU Green Taxonomy. Using practical case studies, respondents are invited to participate in a focus group and survey. Resourcing and knowledge are the main deterrents for firms to implement. Government supports, simplified disclosure requirements and assistance further along the supply-chain will be essential.