Former SNP Deputy Leader Jim Sillars and lead RISE Lothians candidate Colin Fox will launch the RISE election campaign in the Lothians on Thursday evening.
Mr Sillars will tell the meeting at the Grassmarket Centre in Candlemaker Row: "I am backing RISE - Scotland's Left Alliance with my second vote because Scotland desperately needs socialist voices in our Parliament. I urge people to give RISE their second vote too."
Former MSP Colin Fox, who is RISE's top list candidate in the Lothians, welcomed Mr Sillars' endorsement: "Independence remains the elephant in the room in these elections as far as RISE is concerned. The prevailing anti-Tory mood in Scotland suggests that independence is the only way to shed policies we detest.
"Millions of people are suffering with poverty pay, insecurity, and debilitating indebtedness. They feel isolated, exploited and discontented."
RISE candidate Natalie Reid added: "RISE offers a socialist alternative to the Tories. We favour an independent socialist Scotland and a second referendum on independence within the lifetime of this Parliament.
"We want a £10 per hour living wage to end the epidemic of poverty pay. That is the level the UK government says you need to be earning in order to pay your own way. We will scrap the unfair Council Tax and replace it with an income based alternative. We will build 100,000 homes in the socially rented sector and introduce rent controls in the private sector. We will create 100,000 climate change jobs in renewable energy, free public transport, sustainable farming, and fuel efficiency programmes. We will eradicate the scourge of fuel poverty in Scotland in the lifetime of this Parliament again just as the SNP used to promise. That's why people should vote for RISE on 5 May."
Lothians RISE candidate Calum Martin concluded: "It is vitally important that we get RISE MSPs elected to Holyrood to add pressure to the SNP government from the left. They have shown how susceptible they are to pressure from the right.
"Our message could not be clearer. The strength of the Yes movement was its breadth and diversity. That diversity needs sustaining with socialist representation in Parliament."