**2. Conceptual Framework**

Aiming to substantiate the chosen research approach, we present the conceptual background corresponding to the research question. In this regard, we discuss the development and scope of the green marketing concept; later, we move on to the potential of green marketing solutions impacting customer purchasing behavior.

The history of green marketing dates back to the 1960s when the wave of environmental concern led to ecological marketing. This wave was linked to the industries with the most damaging impacts. Since then, the general concept has been represented by such

terms as eco-marketing, ecological marketing, sustainable marketing, and environmental marketing [5].

The scope and meaning of green marketing tend to be misinterpreted [5]. Usually, it is limited to promoting green products [5,12]; however, green marketing involves many more components and activities to meet customers' green demands [13]. Considering the previous research on green marketing [14,15], the definition that closely reveals the spirit of the concept explains green marketing as an "organization's participation in strategic, tactical, and operational marketing activities and processes that have a holistic objective of creating, communicating, and delivering products with minimal environmental impact" [15] (p. 2). In this way, green marketing is concerned with a wide range of strategic, tactical, and operational activities.

At the strategic level, green marketing involves developing strategies to target and selectively appeal to environmentally conscious customers. Defensive or assertive strategies are available based on the prospected size of the green market and marketers' abilities to differentiate green products [16].

The tactical level of green marketing contains solutions related to the marketing mix that drives the organization towards sustainable marketing outcomes, creating value. It is a controllable marketing variable; therefore, the organization can consciously control its influence on customers [2]. It means that product, pricing, distribution, and promotion must clearly emphasize environmental ideas. These marketing mix components become part of green marketing strategies to meet customer demands [7].

Green products may be slight modifications of existing products or truly new green products. The latter may become a source for the company's differentiation; however, at the same time, they are riskier [3]. Green price demonstrated that environmentally sound products are more cost-intensive [5]. The green place's credential resides in renewable energy usage in supply chains [6]. According to Bañares et al. [12], green marketing strongly manifests its significance in advertising. Through advertising, business organizations communicate the environmentally friendly characteristics of their products [17].

At the operational level, green marketing focuses on attracting targeted environmentally conscious customers and efficiently completing the selling process [18]. We suggest marketers concentrate not only on the efficient completion of the selling process, but also on delivering environmental and social values.

Usually, green marketing applies to business-to-customer (B2C) markets; however, Gelderman & Vijgen [19] have proven that this concept is appropriate in business-tobusiness (B2B) or business-to-government (B2G) settings as well. Within the strategic, tactical, and operational contexts, the green customer with his specific behavior in B2C, B2B, or B2G market appears. Green purchasing behavior in any of these markets is generally associated with purchasing in a sustainable, responsible, ethical, and environmentally friendly way. Adopting green behavior is a central facet of achieving sustainability [17].

Seeking to understand green customer behavior, the concept of purchase intention has been featured in a number of studies [2,9,20]. Purchase intention is a crucial factor in predicting customer behavior [2]. Green purchase intention is defined as customers' tendency to pay a price premium for a green product or brand [20]. The increase in purchase intention shows that the possibility of purchasing a particular product by the customer increases correspondingly [2]. It means that marketers must develop marketing solutions that are green in nature to encourage the increase in purchase intention to grow into a purchase decision. However, it is essential to mention that the intention does not always translate into actual purchasing behavior [10,17]. If it translates, there is an opportunity to segment the customers based on their actual behavior. For example, Paço & Varejão [10] suggest segmenting customers who use electrical household appliances and other electrical equipment, air conditioning, and lighting based on their energy-saving behavior into savers and non-carers.

As the research object, green marketing follows two approaches in terms of impact. The first approach focuses on the green marketing influence on customer purchasing

behavior, while the other systematizes the possible effect on the organization (with or without customer purchasing intention as a moderating/mediating variable). This research considers both approaches, with a relevant condition for the second approach. The studies representing the latter approach shall be included in the systematic literature review only if they involve any variable of customer purchasing behavior (as a dependent, moderating, or mediating variable).
